Changes in Low Cloudiness over China between 1971 and 1996

2006 ◽  
Vol 19 (7) ◽  
pp. 1204-1213 ◽  
Author(s):  
Nobuhiko Endo ◽  
Tetsuzo Yasunari
Keyword(s):  
Southern China ◽  
Yangtze River Basin ◽  
Linear Regression Analysis ◽  
Cloud Amount ◽  
Northern China ◽  
Clear Sky ◽  
Low Cloud ◽  
The Yangtze River Basin ◽  
Almost All ◽  
Increasing Trends

Abstract The climatology and long-term trends of low-cloud conditions over China were examined using the Extended Edited Cloud Report Archive data from 1971 to 1996. Linear regression analysis was applied to time series of clear-sky frequencies and low-cloud frequencies, and low-cloud amounts when present. Over the 26-yr study period, the clear-sky frequency increased over northern China. During summer, the frequency of cumuliform clouds decreased over almost all of China. A significant decrease characterized the trend in cumulonimbus (Cb) frequency; however, the Cb cloud amount when present increased over the Yangtze River basin and southern China. Increasing trends in stratocumulus (Sc) cloud amount when present were also observed over much of China.

scholarly journals Potential Driving Factors on Surface Solar Radiation Trends over China in Recent Years

2021 ◽  
Author(s):  
Qiuyan Wang ◽  
Hua Zhang ◽  
Martin Wild
Keyword(s):  
Solar Radiation ◽  
Cloud Cover ◽  
Southern China ◽  
Northern China ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Surface Solar Radiation ◽  
Clear Sky ◽  
Low Cloud ◽  
Low Cloud Cover

<p>The annual mean surface solar radiation (SSR) trends under all-sky, clear-sky, all-sky-no-aerosol, and clear-sky-no-aerosol conditions as well as their possible causes are analyzed during 2005-2018 over China based on different satellite-retrieved datasets to determine the likely drivers of the trends. The results confirm clouds and aerosols as the major contributors to such all-sky SSR trends over China but playing different roles over sub-regions. Aerosol variations during this period result in a widespread brightening, while cloud effects show opposite trends from south to north. Moreover, aerosols contribute more to the increasing all-sky SSR trends over northern China, while clouds dominate the SSR declines over southern China. A radiative transfer model is used to explore the relative contributions of cloud cover from different cloud types to the all-types-of-cloud-cover-induced (ACC-induced) SSR trends during this period in four typical sub-regions over China. The simulations point out that the decreases in low-cloud-cover (LCC) over the North China Plain are the largest positive contributor of all cloud types to the marked annual and seasonal ACC-induced SSR increases, and the positive contributions from both high-cloud-cover (HCC) and LCC declines in summer and winter greatly contribute to the ACC-induced SSR increases over East China. The contributions from medium-low-cloud-cover (mid-LCC) and LCC variations dominate the ACC-caused SSR trends over southwestern and South China all year round, except for the larger HCC contribution in summer.</p>

scholarly journals Potential Driving Factors on Surface Solar Radiation Trends over China in Recent Years

2021 ◽  
Vol 13 (4) ◽  
pp. 704
Author(s):  
Qiuyan Wang ◽  
Hua Zhang ◽  
Su Yang ◽  
Qi Chen ◽  
Xixun Zhou ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Cloud Cover ◽  
Southern China ◽  
Northern China ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Surface Solar Radiation ◽  
Clear Sky ◽  
Low Cloud ◽  
Low Cloud Cover

The annual mean surface solar radiation (SSR) trends under all-sky, clear-sky, all-sky-no-aerosol, and clear-sky-no-aerosol conditions as well as their possible causes are analyzed during 2005–2018 across China based on different satellite-retrieved datasets to determine the major drivers of the trends. The results confirm clouds and aerosols as the major contributors to such all-sky SSR trends over China but play differing roles over sub-regions. Aerosol variations during this period result in a widespread brightening, while cloud effects show opposite trends from south to north. Moreover, aerosols contribute more to the increasing all-sky SSR trends over northern China, while clouds dominate the SSR decline over southern China. A radiative transfer model is used to explore the relative contributions of cloud cover from different cloud types to the all-types-of-cloud-cover-induced (ACC-induced) SSR trends during this period in four typical sub-regions over China. The simulations point out that the decreases in low-cloud-cover (LCC) over the North China Plain are the largest positive contributor of all cloud types to the marked annual and seasonal ACC-induced SSR increases, and the positive contributions from both high-cloud-cover (HCC) and LCC declines in summer and winter greatly contribute to the ACC-induced SSR increases over East China. The contributions from medium-low-cloud-cover (mid-LCC) and LCC variations dominate the ACC-caused SSR trends over southwestern and South China all year round, except for the larger HCC contribution in summer.

scholarly journals Summer Drought Patterns in the Middle-Lower Reaches of the Yangtze River Basin and Their Connections with Atmospheric Circulation before and after 1980

2016 ◽  
Vol 2016 ◽  
pp. 1-18
Author(s):  
Shuping Li ◽  
Guolin Feng ◽  
Wei Hou
Keyword(s):  
River Basin ◽  
Moisture Transport ◽  
Yangtze River ◽  
Southern China ◽  
Yangtze River Basin ◽  
Summer Drought ◽  
The Yangtze River ◽  
Before And After ◽  
Drought Pattern ◽  
The Yangtze River Basin

The three summer drought patterns of the middle-lower reaches of the Yangtze River basin (MLRYRB) and their associated atmospheric circulation were investigated before and after 1980. For the whole-basin wide drought pattern during 1961–1979, the anomalous high ridge over Japan blocked the northerly flow from Siberia to southern China. Further, the western Pacific subtropical high (WPSH) was weaker than normal and shifted eastward. For the southern drought and northern flood pattern during 1961–1979, the zonal circulation was straight and an anomalous anticyclonic circulation was located over Japan. Less moisture was transported to southern China associated with the weakened WPSH. During 1980–2013, the WPSH extended westward and controlled the southern part of the MLRYRB, and an anomalous cyclonic circulation was centered over Japan. For the southern flood and northern drought pattern during 1961–1979, the meridional circulation was obvious, and the WPSH was weaker than normal. The anomalous southwesterly moisture transport appeared to southern China. However, during 1980–2013 the continental high pressure impacted northern China. The WPSH shifted eastward and the anomalous northeasterly moisture transport presented over eastern China.

scholarly journals Observed Quantile Features of Summertime Temperature Trends over China: Non-Negligible Role of Temperature Variability

2021 ◽  
Vol 9 ◽  
Author(s):  
Xing Li ◽  
Xiao Li ◽  
Hedi Ma ◽  
Wenjian Hua ◽  
Shanlei Sun ◽  
...  
Keyword(s):  
Yangtze River Basin ◽  
Northern China ◽  
Temperature Variability ◽  
Ecological Impacts ◽  
Observation Data ◽  
Temperature Trends ◽  
Quantile Regression Analysis ◽  
The Yangtze River Basin ◽  
Mean State

Changes in temperature variability can have more serious social and ecological impacts than changes in the mean state of temperature, especially when they are concurrent with global warming. The present study examines the summertime temperatures’ trends over China from the quantile perspective. Through fully investigating the quantile trends (QTs) of the maximum (Tmax) and minimum temperature (Tmin) using the homogenized observation data and quantile regression analysis, we identify evident region-specific quantile features of summertime temperature trends. In most of northern China, the QTs in Tmax and Tmin for all percentiles generally show strong uniform warmings, which are dominated by a warm shift in mean state temperatures. In contrast, the QTs of Tmax in the Yangtze River Basin show distinguishable inter-quantile features, i.e., an increasing tendency of QTs from cooling trends in the lower percentile to warming trends in the higher percentile. Further investigations show that such robust growing QTs of Tmax across quantiles are dominated by the temperature variance. Our results highlight that more attention should be paid to the region-specific dominance of temperature variability in trends and the related causes.

scholarly journals Spatio-Temporal Variation Analysis of the Biological Boundary Temperature Index Based on Accumulated Temperature: A Case Study of the Yangtze River Basin

2021 ◽  
Vol 10 (10) ◽  
pp. 675
Author(s):  
Guangxun Shi ◽  
Peng Ye ◽  
Xianwu Yang
Keyword(s):  
River Basin ◽  
Yangtze River ◽  
Abrupt Change ◽  
Yangtze River Basin ◽  
The Yangtze River ◽  
Subtropical Zone ◽  
Boundary Temperature ◽  
The Yangtze River Basin ◽  
Accumulated Temperature ◽  
Increasing Trends

Active accumulated temperature is an important index of agricultural heat resources in a region. Based on the temperature data of the Yangtze River Basin from 1970 to 2014, this paper analyzed the characteristics of the temporal and spatial variations of the biological boundary temperature in the Yangtze River Basin. The main conclusions were drawn as follows: (1) since 1970, the accumulated temperature of ≥0 °C in the northern subtropical zone, mid-subtropical zone, and plateau climate zone showed overall increasing trends, and the trends were 122 (p < 0.001), 87.7 (p < 0.001), and 75.3 °C/10a (p < 0.001), respectively. The accumulated temperature of ≥5 °C showed an upward trend, and the change tendency rates were 122.6 (p < 0.001), 90.5 (p < 0.001), and 81.4 °C/10a (p < 0.001), respectively. The accumulated temperature of ≥10 °C showed overall increasing trends and the trends were 115.7 (p < 0.001), 92.5 (p < 0.001), and 78.9 °C/10a (p < 0.001). Accumulated temperatures of ≥0 °C, ≥5 °C, and ≥10 °C in the northern subtropical zone increased significantly higher than that in the mid-subtropical zone and plateau climate zone. (2) The accumulated temperatures of ≥0 °C, ≥5 °C, and ≥10 °C in the northern subtropical zone showed an abrupt change in 1997. In the mid-subtropical zone and plateau climate zone, there was an abrupt change in the accumulated temperatures of ≥0 °C and ≥5 °C in 1994, and in the northern subtropical zone, the abrupt change of the accumulated temperature ≥10 °C occurred in 1998. (3) There are obvious differences in the biological boundary temperature within the Yangtze River Basin, and the stations with large increases are mainly distributed in the middle and lower reaches, such as the Hanshui Basin, the Poyang Lake Basin, the Taihu Lake Basin, and the middle and lower reaches of the mainstream area. The initial day, final day, and continuous days showed a trend of advancement, postponement, and extension, respectively. Besides, the heat resources showed significant increasing trends, which is of guiding significance for the future production and development of agriculture in the region. With the increase of heat resources in the Yangtze River Basin, appropriate late-maturing varieties should be selected in variety breeding, to make full use of heat resources and improve the quality of agricultural products. Secondly, the planting system should be adjusted and the multiple cropping index improved to steadily increase agricultural output. This brings new opportunities to adjust the structure of the agricultural industry and increase farmers’ income, in the Yangtze River basin.

scholarly journals Variability and Trends of High Temperature, High Humidity, and Sultry Weather in the Warm Season in China during the Period 1961–2004

2011 ◽  
Vol 50 (1) ◽  
pp. 127-143 ◽  
Author(s):  
Xiaohui Shi ◽  
Chungu Lu ◽  
Xiangde Xu
Keyword(s):  
High Temperature ◽  
East Asian Monsoon ◽  
Southern China ◽  
Warm Season ◽  
Northern China ◽  
Annual Number ◽  
Daily Maximum ◽  
High Humidity ◽  
Spatial Differences ◽  
Increasing Trends

Abstract Using the daily maximum air temperature and mean humidity observations at 394 surface weather stations across China, the changes in the annual number of days of high temperature weather (HTW), high humidity weather (HHW), and sultry weather (STW) in China over the period 1961–2004 are studied. The results indicate that there were considerable spatial differences and temporal variability of HTW, HHW, and STW across China. Under a climatic mean condition, a notable feature is that southeastern China is the region of collocation of high values of the annual number of days of HTW, HHW, and STW, as well as the region of the most significant variabilities of these parameters. About 55% of the stations in China have increasing trends of the annual number of days of HTW. Most stations in China show decreasing trends of the annual number of days of HHW and are mainly located either in the area south of 30°N or in northern and northeastern China. The stations with increasing trends of the annual number of days of STW are mainly located in northern China, while the stations that have decreasing trends are primarily located in southern China. The analysis results suggest that the variability of the annual number of days of STW corresponds mainly to HTW, and less to HHW. The change in the East Asian monsoon may be responsible for the changes of these statistics in extreme weather in China.

scholarly journals New insights from the combined discrimination of modern/ancient genome-wide shared alleles and haplotypes: Differentiated demographic history reconstruction of Tai-Kadai and Sinitic people in South China

2021 ◽  
Author(s):  
Guanglin He
Keyword(s):  
South China ◽  
Yangtze River ◽  
Southern China ◽  
Yangtze River Basin ◽  
Demographic History ◽  
East Asian ◽  
Han Chinese ◽  
The Yangtze River ◽  
Genome Wide ◽  
The Yangtze River Basin

Southern China was a region with mixed rice-millet farming during the Middle Neolithic period and also suggested to be the homeland of Tai-Kadai-speaking (TK) people. The archaeological evidence of animal and plant domestication has demonstrated that southern Chinese rice agriculturalists dispersed from the Yangtze River basin with the dissemination of TK, Austroasiatic (AA), Austronesian (AN) and Hmong-Mien (HM) languages. However, the formations of the inland TK-speaking people, central/southern Han Chinese and their relationships with Neolithic farmers from the Yangtze and Yellow Rivers (YR) basins are far from clear due to the limited sampling of South China. Here, we revealed the spatiotemporal demographic history of southern China by analyzing newly generated genome-wide data of 70 southeastern mainland TK speakers including Dong, Gelao and Bouyei and 45 southwestern Han Chinese together with comprehensive modern/ancient reference datasets. Southwest Han Chinese and Gelao demonstrated a closer genomic affinity to Neolithic YR farmers, while inland TKs (Dong and Bouyei) demonstrated a closer genomic affinity to coastal TK/AN-speaking islanders and Neolithic Yangtze farmers and their descendants. The shared genetic drift between inland TK/AN speaker highlighted a common origin of AN/TK groups, which may be descended from Tanshishan people or their predecessors (Xitoucun). Additionally, we found that inland TK/Sinitic could be modelled as an admixture of ancestral northern East Asian (ANEA) and ancestral southern East Asian (ASEA) sources with different proportions, in which the ANEA was phylogenetically closer to Neolithic millet farmers deriving from the YR Basin and the ASEA was phylogenetically closer to Coastal Neolithic-to-modern southern East Asians. Finally, we discovered genetic differentiation among TK people from southern China and Southeast Asia and obvious substructures between northern and southern inland Chinese TK people. The observed patterns of the spatiotemporal distribution of the northern and southern East Asian lineages in Central/southern China were also compatible with the scenario of bi-directional gene flow events from ANEA and ASEA. Conclusively, multiple lines of genomic evidence indicated millet farmers deriving from the YR basin and rice farmers deriving from the Yangtze River basin substantially contributed to the present-day mainland TK speakers and Central/southern Han Chinese, and formed the modern dual genetic admixture profile.

scholarly journals Impacts of Spatiotemporal Anomalies of Tibetan Plateau Snow Cover on Summer Precipitation in Eastern China

2017 ◽  
Vol 30 (3) ◽  
pp. 885-903 ◽  
Author(s):  
Chenghai Wang ◽  
Kai Yang ◽  
Yiling Li ◽  
Di Wu ◽  
Yue Bo
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
River Basin ◽  
Yangtze River ◽  
Southern China ◽  
Yangtze River Basin ◽  
Eastern China ◽  
Summer Precipitation ◽  
The Yangtze River ◽  
The Yangtze River Basin

Abstract Tibetan Plateau (TP) snow cover undergoes significant temporal and spatial variations during the winter and spring months. This study investigates the relationship between the spatiotemporal distribution of winter–spring snow cover (SC) over the TP and summer precipitation in eastern China (EC) using the singular value decomposition (SVD) method. Four simulation experiments are designed to validate the results of SVD analysis. Both observations and simulations show that heavier snow cover in the southern TP leads to more rainfall in the Yangtze River basin and northeastern China, and less precipitation in southern China, whereas heavier snow cover in the northern TP results in enhanced rainfall in southeastern and northern China and weakened precipitation in the Yangtze River basin. The linkage is attributed to anomalous westerly winds in the upper troposphere at around 200 hPa and to changes of the southern branch of westerlies at 500 hPa on the south side of the TP, which are caused by lasting diabatic heat anomalies over the TP. The shifts in position of the westerly jet at the exit region and negative anomalies of geopotential height at 500 hPa further result in anomalous anticyclone over the East China Sea and the corresponding 850-hPa water vapor convergence and influence the anomalous summer precipitation belt in EC.

scholarly journals Link between East Asian summer monsoon and sedimentation in river-mouth sandbars since the early Holocene preserved in the Yangtze River subaqueous delta front

2020 ◽  
Vol 95 ◽  
pp. 84-96
Author(s):  
Gang Xu ◽  
Jian Liu ◽  
Marcello Gugliotta ◽  
Yoshiki Saito ◽  
Lilei Chen ◽  
...  
Keyword(s):  
Yangtze River ◽  
Late Holocene ◽  
Asian Summer Monsoon ◽  
Yangtze River Basin ◽  
River Mouth ◽  
Early Holocene ◽  
The Yangtze River ◽  
Delta Front ◽  
The Yangtze River Basin ◽  
Asian Summer

AbstractThis paper presents geochemical and grain-size records since the early Holocene in core ECS0702 with a fine chronology frame obtained from the Yangtze River subaqueous delta front. Since ~9500 cal yr BP, the proxy records of chemical weathering from the Yangtze River basin generally exhibit a Holocene optimum in the early Holocene, a weak East Asian summer monsoon (EASM) period during the middle Holocene, and a relatively strong EASM period in the late Holocene. The ~8.2 and ~4.4 cal ka BP cooling events are recorded in core ECS0702. The flooding events reconstructed by the grain-size parameters since the early Holocene suggest that the floods mainly occurred during strong EASM periods and the Yangtze River mouth sandbar caused by the floods mainly formed in the early and late Holocene. The Yangtze River-mouth sandbars since the early Holocene shifted from north to south, affected by tidal currents and the Coriolis force, and more importantly, controlled by the EASM. Our results are of great significance for enriching both the record of Holocene climate change in the Yangtze River basin and knowledge about the formation and evolution progress of the deltas located in monsoon regions.

Sign in / Sign up

Export Citation Format

Share Document