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Climatology of Cloud-base Height from Long-term Radiosonde Measurements in China

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Advances in Atmospheric Sciences 2018年第2期35卷 158-168页

作者： Yong ZHANG Lejian ZHANG Jianping GUO Jinming FENG Lijuan CAO Yang WANG Qing ZHOU Liangxu LI Bai LI Hui XU Lin LIU Ning AN Huan LIU Meteorological Observation Center China Meteorological Administration State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences National Meteorological Information Center China Meteorological Administration College of Global Change and Earth System Science Beijing Normal University

Clouds are critical to the global radiation budget and hydrological cycle, but knowledge is still poor concerning the observed Climatology of cloud-base height （CBH） in China. Based on fine-resolution sounding observations from the China Radiosonde Network （CRN）, the method used to estimate CBH was modified, and uncertainty analyses indicated that the CBH is good enough. The accuracy of CBH estimation is verified by the comparison between the sounding-derived CBHs and those estimated from the micro-pulse lidar and millimeter-wave cloud radar. As such, the CBH Climatology was compiled for the period 2006-16. Overall, the CBH exhibits large geographic variability across China, at both 0800 Local Standard Time （LST） and 2000 LST, irrespective of season. In addition, the summertime cloud base tends to be elevated to higher altitudes in dry regions [i.e., Inner Mongolia and the North China Plain （NCP）]. By comparison, the Tibetan Plateau （TP）, Pearl River Delta （PRD） and Sichuan Basin （SCB） have relatively low CBHs （〈 2.4 km above ground level）. In terms of seasonality, the CBH reaches its maximum in summer and minimum in winter. A low cloud base tends to occur frequently （〉 70%） over the TP, PRD and SCB. In contrast, at most sites over the Yangtze River Delta （YRD） and the NCP, about half the cloud belongs to the high-cloud category. The CBH does not exhibit marked diurnal variation in summer, throughout all CRN sites, probably due to the persistent cloud coverage caused by the East Asia Summer Monsson. To the best of our knowledge, this is the first CBH Climatology produced from sounding measurements in China, and provides a useful reference for obtaining observational cloud base information.

关键词： cloud base height radiosonde relative humidity China Climatology

BOREAL SUMMER Climatology AND STANDARD DEVIATION IN GLOBAL LOW-FREQUENCY STREAMFUNCTION FIELDS AT 200 hPa

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Journal of Tropical Meteorology 2019年第2期25卷 153-161页

作者：季悦李艳杰吴志伟 Key Laboratory of Meteorology Disaster Ministry of Education (KLME)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD) Nanjing University of Information Science and Technology State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Institute of Atmospheric Sciences Fudan University

Based on NCEP/NCAR DOE daily reanalysis dataset during 1980-2015, this study investigates the boreal summer Climatology and standard deviation of streamfunction in different low frequency periods(including 10-30 days,30-60 days and more than 60 days) at 200 hPa. Distinctions in the characteristics in different periods are emphasized. It is found that the distribution of streamfunction on the timescale longer than 60 days is mainly zonal symmetric,accompanied by strong variability in the Northern Hemisphere subtropical jet streams. For the 10-30-day timescale, it reflects the zonal fluctuating structure in the middle and high latitudes and large variability in the Southern Hemisphere.Tropical quadrupole structure is observed on the 30-60-day timescale in Climatology. Besides, a relative weak standard deviation is also found in this period. This work provides basic knowledge on Climatology and variability in low-frequency streamfunction, which has not been fully illustrated in previous studies.

关键词： low-frequency streamfunction boreal summer Climatology standard deviation

A new global ocean hydrographic Climatology

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Atmospheric and Oceanic Science Letters 2019年第3期12卷 226-229页

作者： GOURETSKI Viktor Center for Earth System Research and Sustainability University of Hamburg International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences

This report describes the main features of the recently published World Ocean Experiment–Argo Global Hydrographic Climatology. This Climatology is based on profile data from ships, Argo floats, and sensors attached to marine mammals. As an important deviation from the widely used climatologies produced previously by the National Oceanographic Data Center, the spatial interpolation was performed on local potential density surfaces, so that no ‘artificial water masses’ were created. In addition to monthly fields of temperature and salinity, gridded maps of the upper mixed layer depth are now provided.

关键词： Global ocean Climatology interpolation method upper mixed layer depth

Climatology of dust storms in northern China and Mongolia： Results from MODIS observations during 2000-2010

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Journal of Geographical Sciences 2015年第11期25卷 1298-1306页

作者： LIU Yang LIU Ronggao State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciencesand Natural Resources Research CAS Beijing 100101 China

The Climatology of dust storms in northern China and Mongolia （33°N-54°N, 73°E-136°E） is characterized at a 1-km resolution based on Moderate Resolution Imaging Spectroradiometer （MODIS） thermal observations during 2000-2010. The dust was extracted with the dynamic reference brightness temperature differences （DRBTD） dust detection algorithm. The major dust source regions are deserts, including the Tarim Basin, Hexi Corridor, Gobi in Mongolia and northern China, Horqin Sandy Land and Qaidam Basin. Dust storms occur most frequently in the Tarim Basin, with a maximum frequency （above 10%） in the eastern narrow inlet of the Taklimakan Desert around Lop Nor. Significant annual and seasonal variations are found for dust events. More than 63.8% of dust events occur in spring from March to May, with the maximum proportion （up to 29.6%） occurring in April. Severe dust storms occur mainly in the deserts in northern and northwestern China, and the largest source region is the eastern narrow inlet and the southern margin of the Taklimakan Desert.

关键词： dust storm Climatology northern China and Mongolia MODIS

Revisiting the Climatology of Atmospheric Blocking in the Northern Hemisphere

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Advances in Atmospheric Sciences 2013年第2期30卷 397-410页

作者： Ho Nam CHEUNG 周文 Hing Yim MOK Man Chi WU Yaping SHAO City University of Hong Kong Shenzhen Research Institute Guy Carpenter Asia-Pacific Climate Impact Centre School of Energy and Environment City University of Hong Kong Hong Kong Observatory Institute for Geophysics and Meteorology University of Cologne

In addition to the occurrence of atmospheric blocking, the Climatology of the characteristics of blocking events, including duration, intensity, and extension, in four seasons over the Northern Hemisphere was analyzed for the period 1950-2009. The seasonality and spatial variations of these characteristics were studied according to their longitudinal distributions. In general, there were sharp discrepancies in the blocking characteristics between winter and summer, and these differences were more prominent over the Atlantic and Pacific Oceans. The blocking not only occurred more frequently but also underwent stronger amplification in winter; likewise, the blocking occurred less frequently and underwent weaker amplification in summer. There are very strong interrelationships among different blocking characteristics, suggesting that they are supported by similar physical factors. In addition, the relationship between blocking over different regions and East Asian circulation was examined. Ural-Siberia is a major blocking formation region in all seasons that may exert a downstream impact on East Asia. The impact is generally weak in summer, which is due to its lower intensity and smaller duration. However, the extratropical circulation over East Asia in summer can be disturbed persistently by the frequent occurrence of blocking over the Asian continent or the Western Pacific. In particular, the blocking frequency over the Western Pacific significantly increased during the study period. This climatological information provides a background for studying the impact of blocking on East Asian circulation under both present and future climate conditions.

关键词： atmospheric blocking Climatology seasonality East Asian circulation

A Climatology OF DEEP CONVECTION OVER SOUTH CHINA AND THE ADJACENT WATERS DURING SUMMER

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Journal of Tropical Meteorology 2013年第1期19卷 1-15页

作者：郑永光陈炯 National Meteorological Centre

Due to the higher temporal and spatial resolution and the better integrality of long-term satellite infrared(IR) Brightness Temperature(TBB) data,a Climatology of deep convection during summer over South China and the adjacent waters is presented in this paper based on the 1-hourly infrared IR TBB data during June-August of 1996-2007(except 2004).The results show that the geographic distribution of deep convection denoted by TBB ≤-52℃ over South China and the adjacent waters are basically consistent with previous statistical results based on surface thunderstorm observations and low-orbit satellite lightning observations.The monthly,ten-day,five-day and diurnal variations of deep convection in this region are focused on in this paper.There are 5 active deep-convection areas in June-August.The monthly variations of the deep convection are closely associated with the large-scale atmospheric circulations.The deep convection over the land areas of South China is more active in June while that over the South China Sea is more active in July and August.The development of deep convection is prominently intermittent and its period is about 3 to 5 five-day periods.However,the deep convection over the coastal areas in South China remains more active during summer and has no apparent intermittence.The ten-day and five-day variations of deep convection show that there are different variations of deep convection over different areas in South China and the adjacent waters.The tendency of deep convection over the land areas of South China is negatively correlated with that over the South China Sea.The diurnal variations of deep convection show that the sea-land breeze,caused by the thermal differences between land and sea,and the mountain-valley breeze,caused by the thermal differences between mountains and plains or basins,cause deep convection to propagate from sea to land in the afternoon and from land to sea after midnight,and the convection over mountains propagates from mountains to plains after midnight.The different diu

关键词： South China Climatology of deep convection IR TBB diurnal variations

Climatology and seasonal variability of satellite-derived chlorophyll a around the Shandong Peninsula

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Journal of Oceanology and Limnology 2021年第4期39卷 1222-1244页

作者： Xiukai SONG Yanzhen GU Fangguo ZHAI Peiliang LI Pengxia LIU Zizhou LIU Wenfan WU Yaozu CHEN Xiangyang JIANG Jianlong HE Shandong Marine Resources and Environment Research Institute Shandong Provincial Key Laboratory of Restoration for Marine EcologyYantai 264006China College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China Institute of Physical Oceanography and Remote Sensing Ocean CollegeZhejiang UniversityZhoushan 316021China Hainan Institute of Zhejiang University Sanya 572025China

The chlorophyll a(Chl a)is an important indicator of marine ecosystems.The spatiotemporal variation of the Chl a greatly aff ects the mariculture and marine ranching in coastal waters of the Shandong Peninsula.In the current study,the Climatology and seasonal variability of surface Chl-a concentration around the Shandong Peninsula are investigated based on 16 years(December 2002-November 2018)of satellite observations.The results indicate that the annual mean Chl-a concentration is greater in the Bohai Sea than in the Yellow Sea and decreases from coastal waters to off shore waters.The highest Chl-a concentrations are found in Laizhou Bay(4.2-8.0 mg/m^(3)),Haizhou Bay(4.2-5.9 mg/m^(3))and the northeast coast of the Shandong Peninsula(4.4-5.0 mg/m^(3)),resulting from the combined eff ects of the intense riverine input and long residence time caused by the concave shape of the coastline.The seasonal Chl-a concentration shows a significant spatial variation.The Chl-a concentrations in these three subregions generally exhibit an annual maximum in August/September,due to the combined eff ects of sea surface temperature,river discharge and sea surface wind.In the southeast coast region,however,the Chl-a concentration is lowest throughout the year and reaches a maximum in February with a minimum in July,forced by the seasonal evolution of the Yellow Sea Cold Water and monsoon winds.The interannual Chl-a concentration trends vary among regions and seasons.There are significant increasing trends over a large area around Haizhou Bay from winter to summer,which are mainly caused by the rising sea surface temperature and eutrophication.In other coastal areas,the Chl-a concentration shows decreasing trends,which are clearest in summer and induced by the weakening land rainfall.This study highlights the differences in the Chl-a dynamics among regions around the Shandong Peninsula and is helpful for further studies of coupled physical-ecological-human interactions at multiple scales.

关键词： chlorophyll-a concentration Shandong Peninsula Climatology seasonal variability Yellow Sea Cold Water

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On the Climatology of Persistent Heavy Rainfall Events in China

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Advances in Atmospheric Sciences 2006年第5期23卷 678-692页

作者：汤燕冰甘晶晶赵璐高坤 Department of Earth Sciences Zhejiang University Hangzhou 310027

Persistent heavy rainfall events （PHR events） comprise one category of weather- and climate- related extreme events. Based on daily rainfall data measured in China during the period of 1951-2004, several quantitative criteria were developed to define PHR events by means of their precipitation intensity, temporal duration, spatial extent and persistence. Then a semi-objective classification based on these criteria was applied to summer daily rainfall data to identify all PHR events. A total of 197 events were observed during the study period. All events were further classified into 5 categories according to their comprehensive intensity; into 3 types according to their circulation regime; and into 8 groups according to the geographic locations of their rainbands. Based on these different classifications, finally, the behaviors of 130 PHR events identified as the most severe, severe and moderate categories since the year of 1951, including characteristics of the spatial and temporal distributions of their frequencies, intensities, and rainbands, were investigated in order to present a comprehensive description of the PHR events. The results will be helpful to the future study of revealing and understanding the processes that govern the production of the PHR events and to the improvement of the forecasts of the PHR events.

关键词： Persistent heavy rainfall extreme precipitation event China Climatology

Microphysical and Dynamical Climatology of Precipitating Systems Inferred by Weather Radar Polarimetric Measurements in Brazil

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Open Journal of Modern Hydrology 2022年第2期12卷 74-93页

作者： Augusto José Pereira Filho Felipe Vemado Departamento de Ciê ncias Atmosféricas Instituto de Astronomia Geofísica e Ci&#234 ncias Atmosféricas Universidade de Sã o Paulo S&#227 o Paulo Brazil

This work presents the Climatology of the microphysics and the dynamics of weather systems in two coastal areas of São Paulo and the Espírito States at high spatial-temporal resolution as measured by two dual Doppler weather radars during the summer and early fall of 2015. Averages and respective standard deviations of polarimetric variables, namely, reflectivity (Z), differential reflectivity (ZDR), differential phase (ϕDP), specific differential phase (KDP), copolar correlation coefficient (ρoHV), radial velocity (Vr), and the spectral width (W) were obtained within a 240-km range on plan position indicator (PPI), constant altitude plan position indicator (CAPPI) and vertical cross-sections to analyze overall horizontal and vertical precipitation microphysics and mesoscale circulation of prevailing weather systems, and their peculiarities over coastal and oceanic, and urban and rural areas. Overall, raindrops tend to be larger over the Metropolitan area of São Paulo from the surface to up to 6 km altitude indicating more vigorous updrafts caused by the heat island effect and the local sea breeze. The vertical microphysical structure is remarkably distinct over the Metropolitan Area of São Paulo (MASP) where thunderstorms can reach 20-km altitude in summertime under sea breeze and heat island effects. On the other hand, there is a dominancy of smaller drop sizes though larger ones observed close to the surface by the coast of Espírito Santo and at the land-ocean interface influenced by the local low-level jet and oceanic-type CCN. Convective cells tend to be smaller associated with Easterlies and more organized with Westerlies. The results indicate distinct features on hydrometeor types and circulation characteristics under these different surface and boundary-layer conditions in close agreement with previous results in the literature.

关键词： Dual Doppler Weather RADAR Microphysics Climatology Atlantic Ocean