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  Subjects -> METEOROLOGY (Total: 106 journals)
Showing 1 - 36 of 36 Journals sorted alphabetically
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 4)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 49)
Advances in Climate Change Research     Open Access   (Followers: 61)
Advances in Meteorology     Open Access   (Followers: 24)
Advances in Statistical Climatology, Meteorology and Oceanography     Open Access   (Followers: 10)
Aeolian Research     Hybrid Journal   (Followers: 7)
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 23)
American Journal of Climate Change     Open Access   (Followers: 41)
Atmósfera     Open Access   (Followers: 2)
Atmosphere     Open Access   (Followers: 33)
Atmosphere-Ocean     Full-text available via subscription   (Followers: 16)
Atmospheric and Oceanic Science Letters     Open Access   (Followers: 9)
Atmospheric Chemistry and Physics (ACP)     Open Access   (Followers: 43)
Atmospheric Chemistry and Physics Discussions (ACPD)     Open Access   (Followers: 16)
Atmospheric Environment     Hybrid Journal   (Followers: 71)
Atmospheric Environment : X     Open Access   (Followers: 3)
Atmospheric Research     Hybrid Journal   (Followers: 71)
Atmospheric Science Letters     Open Access   (Followers: 40)
Boundary-Layer Meteorology     Hybrid Journal   (Followers: 32)
Bulletin of Atmospheric Science and Technology     Hybrid Journal   (Followers: 5)
Bulletin of the American Meteorological Society     Open Access   (Followers: 64)
Carbon Balance and Management     Open Access   (Followers: 6)
Ciencia, Ambiente y Clima     Open Access   (Followers: 1)
Climate     Open Access   (Followers: 8)
Climate and Energy     Full-text available via subscription   (Followers: 11)
Climate Change Economics     Hybrid Journal   (Followers: 52)
Climate Change Responses     Open Access   (Followers: 29)
Climate Dynamics     Hybrid Journal   (Followers: 46)
Climate Law     Hybrid Journal   (Followers: 7)
Climate of the Past (CP)     Open Access   (Followers: 8)
Climate of the Past Discussions (CPD)     Open Access   (Followers: 1)
Climate Policy     Hybrid Journal   (Followers: 60)
Climate Research     Hybrid Journal   (Followers: 7)
Climate Resilience and Sustainability     Open Access   (Followers: 34)
Climate Risk Management     Open Access   (Followers: 11)
Climate Services     Open Access   (Followers: 6)
Climatic Change     Open Access   (Followers: 72)
Current Climate Change Reports     Hybrid Journal   (Followers: 26)
Dynamics and Statistics of the Climate System     Open Access   (Followers: 8)
Dynamics of Atmospheres and Oceans     Hybrid Journal   (Followers: 20)
Earth Perspectives - Transdisciplinarity Enabled     Open Access   (Followers: 1)
Economics of Disasters and Climate Change     Hybrid Journal   (Followers: 18)
Energy & Environment     Hybrid Journal   (Followers: 25)
Environmental and Climate Technologies     Open Access   (Followers: 3)
Environmental Dynamics and Global Climate Change     Open Access   (Followers: 25)
Frontiers in Climate     Open Access   (Followers: 5)
GeoHazards     Open Access   (Followers: 2)
Global Meteorology     Open Access   (Followers: 17)
International Journal of Atmospheric Sciences     Open Access   (Followers: 26)
International Journal of Biometeorology     Hybrid Journal   (Followers: 4)
International Journal of Climate Change Strategies and Management     Hybrid Journal   (Followers: 32)
International Journal of Climatology     Hybrid Journal   (Followers: 29)
International Journal of Environment and Climate Change     Open Access   (Followers: 28)
International Journal of Image and Data Fusion     Hybrid Journal   (Followers: 3)
Journal of Agricultural Meteorology     Open Access  
Journal of Applied Meteorology and Climatology     Hybrid Journal   (Followers: 40)
Journal of Atmospheric and Oceanic Technology     Hybrid Journal   (Followers: 35)
Journal of Atmospheric and Solar-Terrestrial Physics     Hybrid Journal   (Followers: 183)
Journal of Atmospheric Chemistry     Hybrid Journal   (Followers: 24)
Journal of Climate     Hybrid Journal   (Followers: 60)
Journal of Climate Change     Full-text available via subscription   (Followers: 29)
Journal of Climate Change and Health     Open Access   (Followers: 9)
Journal of Climatology     Open Access   (Followers: 4)
Journal of Economic Literature     Hybrid Journal   (Followers: 19)
Journal of Hydrology and Meteorology     Open Access   (Followers: 40)
Journal of Hydrometeorology     Hybrid Journal   (Followers: 9)
Journal of Integrative Environmental Sciences     Hybrid Journal   (Followers: 4)
Journal of Meteorological Research     Full-text available via subscription   (Followers: 3)
Journal of Meteorology and Climate Science     Full-text available via subscription   (Followers: 18)
Journal of Space Weather and Space Climate     Open Access   (Followers: 29)
Journal of the Atmospheric Sciences     Hybrid Journal   (Followers: 84)
Journal of the Meteorological Society of Japan     Partially Free   (Followers: 7)
Journal of Weather Modification     Full-text available via subscription   (Followers: 2)
Mediterranean Marine Science     Open Access   (Followers: 2)
Meteorologica     Open Access   (Followers: 2)
Meteorological Applications     Open Access   (Followers: 5)
Meteorological Monographs     Hybrid Journal   (Followers: 4)
Meteorologische Zeitschrift     Full-text available via subscription   (Followers: 5)
Meteorology     Open Access   (Followers: 19)
Meteorology and Atmospheric Physics     Hybrid Journal   (Followers: 31)
Mètode Science Studies Journal : Annual Review     Open Access  
Michigan Journal of Sustainability     Open Access   (Followers: 1)
Modeling Earth Systems and Environment     Hybrid Journal   (Followers: 1)
Monthly Notices of the Royal Astronomical Society     Hybrid Journal   (Followers: 15)
Monthly Weather Review     Hybrid Journal   (Followers: 30)
Nature Climate Change     Full-text available via subscription   (Followers: 198)
Nature Reports Climate Change     Full-text available via subscription   (Followers: 41)
Nīvār     Open Access   (Followers: 1)
npj Climate and Atmospheric Science     Open Access   (Followers: 6)
Open Atmospheric Science Journal     Open Access   (Followers: 7)
Open Journal of Modern Hydrology     Open Access   (Followers: 6)
Oxford Open Climate Change     Open Access   (Followers: 8)
Revista Iberoamericana de Bioeconomía y Cambio Climático     Open Access   (Followers: 1)
Russian Meteorology and Hydrology     Hybrid Journal   (Followers: 3)
Space Weather     Full-text available via subscription   (Followers: 28)
Studia Geophysica et Geodaetica     Hybrid Journal   (Followers: 1)
Tellus A     Open Access   (Followers: 20)
Tellus B     Open Access   (Followers: 20)
The Cryosphere (TC)     Open Access   (Followers: 13)
The Quarterly Journal of the Royal Meteorological Society     Hybrid Journal   (Followers: 32)
Theoretical and Applied Climatology     Hybrid Journal   (Followers: 13)
Tropical Cyclone Research and Review     Open Access   (Followers: 1)
Urban Climate     Hybrid Journal   (Followers: 4)
Weather and Climate Dynamics     Open Access   (Followers: 3)
Weather and Climate Extremes     Open Access   (Followers: 16)
Weather and Forecasting     Hybrid Journal   (Followers: 41)
Weatherwise     Hybrid Journal   (Followers: 18)
气候与环境研究     Full-text available via subscription   (Followers: 2)

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Acta Meteorologica Sinica
Journal Prestige (SJR): 0.638
Citation Impact (citeScore): 1
Number of Followers: 4  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0894-0525
Published by Springer-Verlag Homepage  [2468 journals]
  • Changes in Atmospheric Circulation during the Winter Regional Extreme Cold
           Events over China since 1960

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      Abstract: Abstract The number of days with occurrence of winter regional extreme cold events (RECEs) in China was found more during 1960/1961-1985/1986 (period 1), less during 1986/1987-2005/2006 (period 2), but more again during 2006/2007-2017/2018 (period 3). So far, the differences in the atmospheric circulation favoring RECEs among these three periods are unclear. In this paper, changes in atmospheric circulation during the RECEs over China are examined by using composite analysis based on the station observed temperature data and NCEP-NCAR reanalysis data in winters of 1960/1961-2017/2018. The results show: (1) the stratospheric polar vortex was more active and tended to split before the outbreak of RECEs in period 3 than that in other two periods. The shift of the stratospheric polar vortex to Eurasia helped the upper Arctic cold air to affect the lower latitudes. (2) The troposphere was characterized by a typical or significant three-wave pattern before the outbreak of RECEs in period 2, in contrast to a weakened three-wave pattern in period 1. Compared to periods 1 and 2, the Okhotsk blocking high was stronger in period 3, contributing to the inverted omega-shaped circulation pattern in East Asia-North Pacific section and a shift of global pattern from three-wave to two-wave. The weakened three-wave or two-wave circulation pattern was manifested by the stronger Ural/Okhotsk blocking high, conducive to the strengthening of the meridional circulation and the occurrence of RECEs in East Asia. (3) The Siberian high was the strongest in period 3, followed by period 1, and it was the weakest in period 2. Before the outbreak of RECEs, the Siberian high in period 3 began to intensify one week earlier than that in periods 1 and 2. Thus, the accumulation time of cold air mass in period 3 was the longest. In summary, the synergism of atmospheric circulation at high and low levels in periods 1 and 3 was more conducive to more and strong RECEs than that in period 2. Moreover, the split of the stratospheric polar vortex may have played an important role on the formation of tropospheric two-wave pattern in period 3. The results obtained herein may provide a better understanding of the mechanisms for occurrences of RECEs in China.
      PubDate: 2023-10-01
       
  • Random Forest-Based Snow Cover Mapping in China Using Fengyun-3B VIRR Data

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      Abstract: Abstract Currently, there is variability in the spectral band thresholds for snow cover recognition using remote sensing in different regions and for complex terrains. Using Fengyun-3B Visible and Infra-Red Radiometer (FY-3B VIRR) satellite data, we applied random forest (RF) methodology and selected 13 feature variables to obtain snow cover. A training set was generated, containing approximately 1 million snow and nonsnow samples obtained in China from the snow monitoring reports issued by the National Satellite Meteorological Centre and four snow cover products from the Interactive Multi-sensor Snow and Ice Mapping System (IMS), the FY-3B Multi-Sensor Synergy (MULSS), the Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover product (MYD10A1), and the National Cryosphere Desert Data Center (NCDC). This training set contained many different samples of cloud types and snow under forest cover to help effectively distinguish snow and clouds and improve the recognition rate of snow under forest cover. Then, two RF snow cover recognition models were constructed for the snow and nonsnow seasons and they were used to conduct daily snow cover recognition in China from 2011 to 2020. The results show that the RF models constructed based on FY-3B VIRR data have good recognition performance for shallow snow, understory snow, and snow on the Qinghai-Tibetan Plateau. The recognition accuracy against weather stations and the spatial consistency with the IMS product are better than the MULSS, MYD10A1, and NCDC products. The overall accuracy of the RF product is 90.6%, and the recall rate is 93.8%. The omission and commission errors are 6.2% and 11.1%, respectively. Unlike other existing snow cover algorithms, the established RF model skips the complicated atmospheric correction and cloud identification processes and does not involve external auxiliary data; thus, it is more easily popularized and operationally applicable to generating long-time series snow cover products.
      PubDate: 2023-10-01
       
  • Predictability and Risk of Extreme Winter PM2.5 Concentration in Beijing

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      Abstract: Abstract Air pollution remains a serious environmental and social problem in many big cities in the world. How to predict and estimate the risk of extreme air pollution is unsettled yet. This study tries to provide a solution to this challenge by examining the winter PM2.5 concentration in Beijing based on the UNprecedented Simulation of Extremes with ENsembles (UNSEEN) method. The PM2.5 concentration observations in Beijing, Japanese 55-yr reanalysis data, and the Met Office near term climate prediction system (DePreSys3a) large ensemble simulations are used, and 10,000 proxy series are generated with the model fidelity test. It is found that in Beijing, the main meteorological driver of PM2.5 concentration is monthly 850-hPa meridional wind (V850). Although the skill in prediction of V850 is low on seasonal and longer timescales, based on the UNSEEN, we use large ensemble of initialized climate simulations of V850 to estimate the current chance and risk of unprecedented PM2.5 concentration in Beijing. We unravel that there is a 3% (2.1%–3.9%) chance of unprecedented low monthly V850 corresponding to high PM2.5 in each winter, within the 95% range, calculated by bootstrap resampling of the data. Moreover, we use the relationship between air quality and winds to remove the meridional wind influence from the observed record, and find that anthropogenic intervention appears to have reduced the risk of extreme PM2.5 in Beijing in recent years.
      PubDate: 2023-10-01
       
  • Changes in Persistent Precipitation in Northwest China and Related
           Large-Scale Circulation Features

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      Abstract: Abstract Based on China’s daily precipitation data of 2415 stations and ERA5 hourly reanalysis data from 1961 to 2019, the station-based and regional precipitation events over Northwest China (NWC) are identified and sorted into persistent precipitation (PP, duration & 2 days) events and non-persistent precipitation (NPP, duration = 1 day) events; and then changes in the persistence structure of the PP and NPP events over NWC and the long-term mean adjustment of the related large-scale circulation configuration are analyzed. The results show that PP and NPP both witness an increasing trend over most parts of NWC. In terms of the total precipitation at most stations and the regional mean, contributions from PP have been increasing, while those from NPP have been decreasing. This demonstrates that the wetting trend in NWC is mainly caused by the increase in PP. Through analyzing the large-scale circulation corresponding to regional PP events at several representative levels, we found that the westerly jet at 200 hPa, the ridge/trough systems at 500 hPa, and the Mongolian low at sea level are the key circulation systems responsible for regional PP events over NWC. As for long-term mean changes after and before 1990 (a shifting point recognized by previous studies), it is found that the extent of the South Asian high becomes larger and the westerly jet shifts northward by approximately 1.5 degrees in the upper troposphere. The ridge near the Ural Mountains and the ridge downstream of NWC strengthen by approximately 10–30 hPa at 500 hPa. Furthermore, the difference between the Mongolian low trough and its surrounding high pressure increases by approximately 2 hPa at the sea level. The combinations of circulation changes from upper to lower levels facilitate the strengthening of ascending motions. These adjustments in circulations create more favorable conditions for PP to occur over NWC in the last three decades.
      PubDate: 2023-10-01
       
  • Operational Plan, Effect Verification, and Key Technical Settings for a
           Stadium-Scale Artificial Rain Reduction Experiment

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      Abstract: Abstract To explore the key technologies of artificial weather modification for specific targets (e.g., a stadium) and improve the efficiency of artificial rainfall modification for major events, this study conducts an artificial rainfall reduction experiment for the closing ceremony of Nanjing Youth Olympic Games on 28 August 2014. Satellite retrievals, radar observations, sounding data, and other sources of information as well as Cloud and Precipitation Accurate Analysis System (CPAS) are used in this study. The main conclusions are as follows. (1) On 28 August 2014, a large-scale cumulus cloud system with mixed-phase stratocumulus and stratus precipitation was observed. This system was influenced by the weak shear of a low-level trough and the precipitation was dominated by cold clouds with dry layers between clouds. Thereby, we adopted the crystal-priming over-catalytic hypothesis and conducted a rocket-catalytic rain abatement operation at a certain distance (100–25 km) from the stadium. Rocket shootings of different intensities were implemented for two echoes that affected the stadium successively (two rounds of 15 rocket shootings within 15 min for an isolated weak echo IA; multiple rounds of 156 rocket shootings within 80 min for a strong echo IB). Amazingly, after the shootings with the catalysis in the air, reflectivity of the two echoes was reduced at all altitudes with the most significant reduction at the 2-km altitude, and the time needed for the obvious reduction was 40 min. The most obvious reduction of the two echoes then maintained for 60 and 53 min, respectively, and the operation time needed for the echo zone to recover after the stop of rocket shooting was 108 min for echo IA and 90 min for echo IB. The two echoes moving across the stadium during the time period of the closing ceremony (2000–2130 local time) were at their minimal strengths, with almost no echo over the target stadium. This demonstrates that the rocket shooting strategy of over-crystallization catalysis is effective, and the shooting site, time, and dose are reasonable. The following technical parameters were used during this experiment. At about 80–25 km away from the target stadium in the west, the rocket shooting lasted for 15–80 min and the doses were not less than 1 shot min−1 (1 shot min−1 for echo IA, 2.25 shots min−1 for echo IB). The attenuation rate was 0.21 dBZ min−1 for the average 15 dBZ of echo IA. For the average 25 dBZ of echo IB, the attenuation rate was 0.27 dBZ min−1. The above technical settings helped achieve the goal of reducing rain over the stadium to almost zero for nearly 1-h period during the critical time of the event.
      PubDate: 2023-10-01
       
  • Variation of Dust in Northern China and Its Reproduction in BCC-ESM1 since
           1980

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      Abstract: Abstract In this paper, we explore the possible causes and mechanisms for the variation of dust in northern China from 1980 to 2014 using the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2) data, observational data, and BCC-ESM1 (Beijing Climate Center Earth System Model version 1) simulation data. Two important dust centers are identified in China: one in the Taklamakan Desert in southern Xinjiang Region and the other in the Badain Jaran Desert in western Inner Mongolia Plateau. Both centers display distinct seasonal variations, with high dust concentration in spring and summer and low in autumn and winter. BCC-ESM1 is able to generally capture the main spatial and temporal characteristics of dust in northern China. Both the MERRA-2 reanalysis data and BCC-ESM1 simulation data show a decreasing trend in spring dust, which is evident during 1980–2000 and 2001–2014. The analysis based on daily mean dust loads and wind fields from MERRA-2 and BCC-ESM1 indicates that dusty weather in North China may be mainly caused by transport of the dust, especially that from the central and western Inner Mongolia Plateau during the prior 0–2 days, through the westerly winds from the upstream “dust core” region (38°–45°N, 90°–105°E). This is one of the important paths for dust to move into North China. The weakened westerly wind in the lower troposphere in this “dust core” region may be responsible for the reduction of spring dust in North China.
      PubDate: 2023-10-01
       
  • Cloud Microphysical Processes and Atmospheric Water Budget during the 20
           July 2021 Extreme Precipitation Event in Zhengzhou, China

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      Abstract: Abstract This study investigated the cloud microphysical processes and atmospheric water budget during the extreme precipitation event on 20 July 2021 in Zhengzhou of Henan Province, China, based on observations, reanalysis data, and the results from the high-resolution large-eddy simulation nested in the Weather Research and Forecasting (WRF) model with assimilation of satellite and radar observations. The results show that the abundant and persistent southeasterly supply of water vapor, induced by Typhoons In-Fa and Cempaka, under a particular synoptic pattern featured with abnormal northwestward displacement of the western Pacific subtropical high, was conducive to warm rain processes through a high vapor condensation rate of cloud water and an efficient collision–coalescence process of cloud water to rainwater. Such conditions were favorable for the formation and maintenance of the quasi-stationary warm-sector heavy rainfall. Precipitation formation through the collision–coalescence process of cloud water to rainwater accounted for approximately 70% of the total, while the melting of snow and graupel accounted for only approximately 30%, indicating that warm cloud processes played a dominant role in this extreme rainfall event. However, enhancement of cold cloud processes promoted by latent heat release also exerted positive effect on rainfall during the period of most intense hourly rainfall. It was also found that rainwater advection from outside of Zhengzhou City played an important role in maintaining the extreme precipitation event.
      PubDate: 2023-10-01
       
  • Refined Spatialization of 10-Day Precipitation in China Based on GPM IMERG
           Data and Terrain Decomposition Using the BEMD Algorithm

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      Abstract: Abstract Continuous high spatial-resolution 10-day precipitation data are essential for crop growth services and phenological research. In this study, we first use the bidimensional empirical mode decomposition (BEMD) algorithm to decompose the digital elevation model (DEM) data and obtain high-frequency (OR3), intermediate-frequency (OR5), and low-frequency (OR8) margin terrains. Then, we propose a refined precipitation spatialization model, which uses ground-based meteorological observation data, integrated multi-satellite retrievals for global precipitation measurement (GPM IMERG) satellite precipitation products, DEM data, terrain decomposition data, prevailing precipitation direction (PPD) data, and other multisource data, to construct China’ s high-resolution 10-day precipitation data from 2001 to 2018. The decomposition results show mountainous terrain from fine to coarse scales; and the influences of altitude, slope, and aspect on precipitation are better represented in the model after topography is decomposed. Moreover, terrain decomposition data can be added to the model simulation to improve the quality of the simulation product; the simulation quality of the model in summer is better than that in spring and autumn, and is relatively poor in winter; and OR5 and OR8 can be improved in the simulation, with better OR5 and OR8 dynamically selected. In addition, preprocessing the data before precipitation spatialization is particularly important. For example, adding 0.01 to the 0 value of precipitation, multiplying the small value of precipitation less than 1 by 10, and performing the normal distributions transform (e.g., Yeo–Johnson) on the data can improve the simulation quality.
      PubDate: 2023-10-01
       
  • Impacts of Extreme Droughts on Ecosystem Water Use Efficiency Diverge
           between Forest and Grassland

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      Abstract: Abstract Ecosystem-scale water use efficiency (WUE), as a quantification of the coupling between carbon and water cycle, determines whether vegetation could survive under severe drought stress. Nevertheless, how extreme droughts affect ecosystem-scale WUE and its difference among regions and biomes are still poorly understood. In this study, using data-oriented gridded products of gross primary productivity (GPP) and evapotranspiration (ET), we assessed the ecosystem WUE change during extreme drought years over China, and further compared drought impacts on WUE between forest and grassland ecosystems. We found a spatial heterogeneity of WUE change in response to extreme droughts across regions. Particularly, grassland WUE was substantially reduced concurrent with suppressed photosynthesis, while most of forest exhibited slightly decreased or even increased WUE under extreme droughts. In addition, we demonstrated that drought characteristics and environmental conditions modulated drought impacts on WUE. Temperature anomalies during droughts and leaf area were found to be the predominant factors driving WUE change for both forest and grassland. With increasing occurrence of compound dry and hot extremes, our results, therefore, would be an insightful supplement to the current understanding of the influence of extreme events on terrestrial ecosystems.
      PubDate: 2023-10-01
       
  • First Look of Surface Vegetation from the Advanced Geostationary Radiation
           Imager (AGRI) onboard Fengyun-4B

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      Abstract: Abstract For many years, the status of surface vegetation has been monitored by using polar-orbiting satellite imagers such as Moderate Resolution Imaging Spectroradiometer (MODIS). However, limited availability of clear-sky samples makes the derived vegetation index dependent on multiple days of observations. High-frequency observations from the geostationary Fengyun (FY) satellites can significantly reduce the influence of clouds on the synthesis of terrestrial normalized difference vegetation index (NDVI). In this study, we derived the land surface vegetation index based on observational data from the Advanced Geostationary Radiation Imager (AGRI) onboard the FY-4B geostationary satellite. First, the AGRI reflectance of visible band and near-infrared band is corrected to the land surface reflectance by the 6S radiative transfer model. The bidirectional reflectance distribution function (BRDF) model is then used to normalize the AGRI surface reflectance at different observation angles and solar geometries, and an angle-independent reflectance is derived. The AGRI surface reflectance is further corrected to the MODIS levels according to the AGRI spectral response function (SRF). Finally, the daily AGRI data are used to synthesize the surface vegetation index. It is shown that the spatial distribution of NDVI images retrieved by single-day AGRI is consistent with that of 16-day MODIS data. At the same time, the dynamic range of the revised NDVI is closer to that of MODIS.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-3005-x
       
  • Shape Classification of Cloud Particles Recorded by the 2D-S Imaging Probe
           Using a Convolutional Neural Network

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      Abstract: Abstract The airborne two-dimensional stereo (2D-S) optical array probe has been operating for more than 10 yr, accumulating a large amount of cloud particle image data. However, due to the lack of reliable and unbiased classification tools, our ability to extract meaningful morphological information related to cloud microphysical processes is limited. To solve this issue, we propose a novel classification algorithm for 2D-S cloud particle images based on a convolutional neural network (CNN), named CNN-2DS. A 2D-S cloud particle shape dataset was established by using the 2D-S cloud particle images observed from 13 aircraft detection flights in 6 regions of China (Northeast, Northwest, North, East, Central, and South China). This dataset contains 33,300 cloud particle images with 8 types of cloud particle shape (linear, sphere, dendrite, aggregate, graupel, plate, donut, and irregular). The CNN-2DS model was trained and tested based on the established 2D-S dataset. Experimental results show that the CNN-2DS model can accurately identify cloud particles with an average classification accuracy of 97%. Compared with other common classification models [e.g., Vision Transformer (ViT) and Residual Neural Network (ResNet)], the CNN-2DS model is lightweight (few parameters) and fast in calculations, and has the highest classification accuracy. In a word, the proposed CNN-2DS model is effective and reliable for the classification of cloud particles detected by the 2D-S probe.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-2146-2
       
  • Future Drought Changes in China Projected by the CMIP6 Models:
           Contributions from Key Factors

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      Abstract: Abstract Model simulations show that drought may become more severe and widespread in the 21st century due to human-induced global warming. However, the contributions from the key factors to the model-projected drought changes in China have not yet been examined in detail. We used the self-calibrated Palmer Drought Severity Index with Penman–Monteith potential evapotranspiration (scPDSIpm) based on 10 model simulations selected from the Coupled Model Intercomparison Project Phase 6 (CMIP6). We investigated the contributions from precipitation (P), near-surface air temperature and specific humidity [Δ(T + q)], net surface longwave radiation (LW), net surface shortwave radiation (SW), and wind speed (WS) to the future changes in scPDSIpm, including the long-term mean, drying area, probability distribution function (PDF), drought frequency, and drought duration based on the scPDSIpm over China. Our results show that model-projected drying mainly occurs over southern China, whereas the dry areas under drought conditions increase from 20% to about 23%/30% under the two scenarios of the shared socioeconomic pathway (SSP2-4.5/SSP5-8.5) from 1985 to 2100, despite large uncertainties in individual projections partly due to internal variability. Drought frequency is projected to increases by about 10%–54% (15%–88%) under the SSP2-4.5 (SSP5-8.5) scenario by the late 21st century, along with increases in drought duration. These changes are accompanied by a decrease in the mean scPDSIpm and flattening of the PDFs. The changes in drying over southern China are mainly attributed to surface warming and the increased surface vapor pressure deficit (VPD), with small contributions from changes in the surface net radiation. The changes in wetting over northern China mostly result from increased precipitation along with a small wetting effect from the changes in wind speed.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-2169-8
       
  • Disastrous Persistent Extreme Rainfall Events of the 2022 Pre-Flood Season
           in South China: Causes and Subseasonal Predictions

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      Abstract: Abstract Two persistent extreme rainfall events (PEREs) with record-breaking amounts of rainfall and long duration caused disastrous impact during the 2022 pre-flood season in South China. Atmospheric intraseasonal variability played a key role in triggering and maintaining both PEREs, but its major impact on each event was associated with different modes. For the first PERE (10–15 May; PERE1), the tropical and extratropical quasi-biweekly oscillations jointly contributed to the extreme rainfall intensity. In contrast, the long duration (6–21 June) of the heavy rainfall during the second PERE (PERE2) was closely related to prolonged convection and moisture transport anomalies induced mainly by the tropical 30–90-day variability. Subseasonal-to-seasonal predictions by the model of the ECMWF showed limited skill in relation to the rainfall intensity of PERE1 and PERE2 beyond 1–2 weeks. Further assessment suggested that the fidelity of the PERE predictions was linked to model skill in predicting the phase evolution and intensity of tropical and extratropical intraseasonal variabilities. Thus, efficient monitoring and accurate prediction of the various modes of atmospheric intraseasonal variability are fundamental to reducing the hazard associated with PEREs in South China.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-3014-9
       
  • Adaptive Statistical Spatial Downscaling of Precipitation Supported by
           High-Resolution Atmospheric Simulation Data for Mountainous Areas of Nepal
           

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      Abstract: Abstract In complex terrain regions, it is very challenging to obtain high accuracy and resolution precipitation data that are required in land hydrological studies. In this study, an adaptive precipitation downscaling method is proposed based on the statistical downscaling model MicroMet. A key input parameter in the MicroMet is the precipitation adjustment factor (PAF) that shows the elevation dependence of precipitation. Its value is estimated conventionally based on station observations and suffers sparse stations in high altitudes. This study proposes to estimate the PAF value and its spatial variability with precipitation data from high-resolution atmospheric simulations and tests the idea in Nepal of South Himalayas, where rainfall stations are relatively dense. The result shows that MicroMet performs the best with the PAF value estimated from the simulation data at the scale of approximately 1.5 degrees. Not only the value at this scale is qualitatively consistent with early knowledge obtained from intensive observations, but also the downscaling performance with this value is better than or comparable to that with the PAF estimated from dense station data. Finally, it is shown that the PAF estimation, although critical, cannot replace the importance of increasing input station density for downscaling.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-3017-6
       
  • Impact of Cold Spells on Ischemic Stroke Severity and Clinical Outcomes in
           Tianjin, China

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      Abstract: Abstract There are several studies on the impact of extreme weather on the incidence and mortality of stroke, but the research on the effect of extreme weather events on severity and outcome of ischemic stroke is scarce. This study aimed to evaluate the impact of cold spells on the severity and clinical outcomes of patients with initial acute ischemic stroke in a hospital-based study. We enrolled 553 patients with initial ischemic stroke during the cold seasons between 2016 and 2019. Patients were separated into the mild stroke group and moderate-to-severe stroke group according to the National Institutes of Health Stroke Scale (NIHSS) of the U.S., and good outcome group and poor outcome group according to modified Rankin Scale (mRS) scores. There are nine different definitions of cold spells according to intensities and duration time. After adjustment for climate factors, air quality index, and common risk factors, it is found that cold spells were associated with moderate-to-severe neurological deficits and clinical outcomes in overall ischemic stroke patients. Furthermore, the delay effect for stroke severity started at the beginning of the cold wave (Lag 0) and lasted up to 14 days (Lags 0–14). In addition, when a cold spell was set as a daily mean temperature < 3rd or 5th percentile and with a duration ⩾ 2 or 3 consecutive days, cold spells had a significant impact on clinical outcomes, and there was a definite delay effect of at least 7 days (Lags 0–7) and it lasted up to 14 days (Lags 0–14). At last, we concluded that cold spells may be a contributory factor for more severe neurological deficits and worse outcomes in patients with initial ischemic stroke.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-2159-x
       
  • A Thorough Evaluation of the Passive Microwave Radiometer Measurements
           onboard Three Fengyun-3 Satellites

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      Abstract: Abstract Microwave Radiometer Imager (MWRI) is a key payload of China’s second generation polar meteorological satellite, i.e., Fengyun-3 series (FY-3). Up to now, 5 satellites including FY-3A (2008), FY-3B (2010), FY-3C (2013), FY-3D (2018), and FY-3E (2021) have been launched successfully to provide multiwavelength, all-weather, and global data for decades. Much progress has been made on the calibration of MWRI and a recalibrated MWRI brightness temperature (BT) product (V2) was recently released. This study thoroughly evaluates the accuracy of this new product from FY-3B, 3C, and 3D by using the simultaneous collocated Global Precipitation Measurement (GPM) Microwave Imager (GMI) measurements as a reference. The results show that the mean biases (MBEs) of the BT between MWRI and GMI are generally less than 0.5 K and the root mean squares (RMSs) between them are less than 1.5 K. The previous notable ascending and descending difference of the MWRI has disappeared. This indicates that the new MWRI recalibration procedure is very effective in removing potential errors associated with the emission of the hot-load reflector. Analysis of the dependence of MBE on the latitude and earth scene temperature shows that MBE decreases with decreasing latitude over ocean. Furthermore, MBE over ocean decreases linearly with increasing scene temperature for almost all channels, whereas this does not occur over land. A linear regression fitting is then used to modify MWRI, which can reduce the MBE over ocean to be within 0.2 K. The standard deviation of error of GMI, FY-3B, and FY-3D MWRI BT data derived by using the three-cornered hat method (TCH) shows that GMI has the best overall performance over ocean except at 10.65 GHz where its standard deviation of error is slightly larger than that of FY-3D. Over land, the standard deviation of error of FY-3D is the lowest at almost all channels except at 89V. MWRI onboard FY-3 series satellites would serve as an important passive microwave radiometer member of the constellation to monitor key surface and atmospheric properties.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-2198-3
       
  • Unusual Evolution of the Multiple Eyewall Cycles in Super Typhoon
           Hinnamnor (2022)

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      Abstract: Abstract Hinnamnor was the first super typhoon in the western North Pacific basin in 2022. It had several prominent characteristics, such as rapid intensification after its formation, three eyewall cycles, and a sudden recurvature of its track. Based on multi-source observational and reanalysis datasets, two secondary eyewall formation (SEF) cycles occurred during Super Typhoon Hinnamnor’s lifetime. The first SEF happened near the time when Hinnamnor achieved its maximum intensity, and it seems that its internal dynamics dominated the SEF process after the development of shear-induced asymmetric spiral rainbands. The merger of a tropical depression with Hinnamnor led to a continuous increase in both its inner-core size and outer-core circulation, causing generation of the second SEF. It is inferred that the external and internal dynamics worked together during the second SEF process. The concentric eyewall structure maintained for approximately 84 h under the moderate vertical wind shear. Also, unique changes in intensity accompanied the two structural changes.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-2193-8
       
  • Zonally Asymmetric Temperature Trends near the Northern Middle and High
           Latitude Stratopause during Winter

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      Abstract: Abstract The temperature trend near the stratopause is rarely evaluated owing to the limited long-term observations of global temperature. In this study, the spatial patterns of the temperature trends near the northern stratopause are investigated by using satellite and reanalysis datasets. Our analysis reveals a zonally asymmetric temperature trend pattern near the northern mid-to-high latitude stratopause during January, and this pattern underwent an evident transition around the 2000s. From 1980 to 2003, there was a cooling trend in the Western Hemisphere and a warming trend in the Eastern Hemisphere. In contrast, a reversed zonally asymmetric temperature trend pattern existed in the east-west direction from 2003 to 2020. Although the warming trends are statistically insignificant, they contrasted with the overall cooling trend in the upper stratosphere due to ozone depletion and an increase in well-mixed greenhouse gases in recent decades. The zonally asymmetric temperature trends were induced by the transition in the intensity of quasi-stationary planetary wavenumber 1 (wave 1) near the stratopause. The increasing (decreasing) trend of the intensity of wave 1 enhanced (weakened) its meridional temperature advection near the stratopause before (after) the 2000s; consequently, a zonally asymmetric temperature trend pattern exists in the east–west direction near the stratopause. The transition in the intensity of the stratospheric wave 1 around the 2000s is most likely caused by the transition in the intensity of wave 1 activity in the troposphere.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-3015-8
       
  • Efficiently Improving Ensemble Forecasts of Warm-Sector Heavy Rainfall
           over Coastal Southern China: Targeted Assimilation to Reduce the Critical
           Initial Field Errors

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      Abstract: Abstract Warm-sector heavy rainfall events over southern China are difficult to accurately forecast, due in part to inaccurate initial fields in numerical weather prediction models. In order to determine an efficient way of reducing the critical initial field errors, this study conducts and compares two sets of 60-member ensemble forecast experiments of a warm-sector heavy rainfall event over coastal southern China without data assimilation (NODA) and with radar radial velocity data assimilation (RadarDA). Yangjiang radar data, which can provide offshore high-resolution wind field information, were assimilated by using a Weather Research and Forecasting (WRF)-based ensemble Kalman filter (EnKF) system. The results show that the speed and direction errors of the southeasterly airflow in the marine boundary layer over the northern South China Sea may primarily be responsible for the forecast errors in rainfall and convection evolution. Targeted assimilation of radial velocity data from the Yangjiang radar can reduce the critical initial field errors of most members, resulting in improvements to the ensemble forecast. Specifically, RadarDA simulations indicate that radial-velocity data assimilation (VrDA) can directly reduce the initial field errors in wind speed and direction, and indirectly and slightly adjust the initial moisture fields in most members, thereby improving the evolution features of moisture transport during the subsequent forecast period. Therefore, these RadarDA members can better capture the initiation and development of convection and have higher forecast skill for the convection evolution and rainfall. The improvement in the deterministic forecasts of most members results in an improved overall ensemble forecast performance. However, VrDA sometimes results in inappropriate adjustment of the initial wind field, so the forecast skill of a few members decreases rather than increases after VrDA. This suggests that a degree of uncertainty remains about the effect of the WRF-based EnKF system. Moreover, the results further indicate that accurate forecasts of the convection evolution and rainfall of warm-sector heavy rainfall events over southern China are challenging.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-2140-8
       
  • Variation in Sunshine Duration and Related Aerosol Influences at
           Shangdianzi GAW Station, China: 1958–2021

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      Abstract: Abstract Sunshine duration (SD) is adopted widely to study global dimming/brightening. However, long-term simultaneous measurements of SD and closely related impact factors require further analysis to elucidate how and why SD has varied during the past decades. In this study, a long-term (1958–2021) SD data series obtained from the Shangdianzi Global Atmosphere Watch (GAW) station in China was analyzed to detect linear trends, climatic jumps, and climatic periods in SD using linear fitting, the Mann–Kendall trend test, and the continuous wavelet transform method. Annual SD exhibited steady dimming (−67.3 h decade−1) before 2010, followed by a period of brightening (189.9 h decade−1) during 2011–2020. An abrupt jump in annual SD occurred in 1995, and the annual SD anomaly exhibited significant oscillation with ∼3-yr periodicity during 1960–1978. Partial least squares analysis revealed that annual SD anomaly was associated with variations in relative humidity, gale days, cloud cover, and black carbon (BC). Further analysis of the clear-sky daily sunshine percentage (DSP) and simultaneous measurements of aerosol properties, including aerosol optical depth, aerosol extinction coefficient, single scattering albedo (SSA), BC, and total suspended particulates, suggested that variation in DSP was affected primarily by aerosol scattering and absorption. Furthermore, the hourly clear-sky SD at high aerosol loading was approximately 60% and 56% of that at middle and low aerosol loadings, respectively. The pattern of diurnal variation in clear-sky hourly SD, as well as the actual values, can be affected by the fine particulate concentration, aerosol extinction coefficient, and SSA.
      PubDate: 2023-08-01
      DOI: 10.1007/s13351-023-2196-5
       
 
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