scholarly journals Hourly Rainfall Changes in Response to Surface Air Temperature over Eastern Contiguous China

2012 ◽  
Vol 25 (19) ◽  
pp. 6851-6861 ◽  
Author(s):  
Rucong Yu ◽  
Jian Li
Keyword(s):  
Air Temperature ◽  
Extreme Precipitation ◽  
Eastern China ◽  
Surface Air Temperature ◽  
Late Summer ◽  
Extreme Rainfall ◽  
Summer Rainfall ◽  
Intense Rainfall ◽  
Mean Values ◽  
Hourly Rainfall

Abstract In this study, late-summer rainfall over eastern contiguous China is classified according to hourly intensity and the changes of moderate, intense, and extreme precipitation in response to variation of surface air temperature are analyzed. The e-folding decay intensity (Imi) derived from the exponential distribution of rainfall amount is defined as the threshold that partitions rainfall into moderate and intense rainfall, and the double e-folding decay intensity (Ie) is used as the threshold to pick out extreme cases. The mean values of Imi and Ie are about 12 and 24 mm h−1, respectively. Between the two periods, 1966–85 and 1986–2005, the ratio between moderate and intense rainfall has experienced significant changes. And the spatial pattern of changes in the percentage of moderate rainfall presents a direct relation with that of the surface air temperature. Based on temperature changes, three regimes, regime N (north China), regime C (central eastern China), and regime S (southeastern coastal area of China), are defined. In warming regimes (regimes N and S), the percentage of moderate rainfall exhibits a decreasing trend. In regime C, where the temperature has fallen, the percentage of moderate rainfall increased prominently. In all three regimes there are significant negative (positive) correlations between the percentage of moderate (intense) rainfall and the temperature. The relation between the extreme rainfall and the surface air temperature is far more regionally dependent. With plenty of water supply and little change in relative humidity, the extreme rainfall increased in regime S. Although regime N also shows strong warming trends, there is no significant trend in extreme precipitation due to the lack of water vapor transportation.

scholarly journals Changes in Characteristics of Late-Summer Precipitation over Eastern China in the Past 40 Years Revealed by Hourly Precipitation Data

2010 ◽  
Vol 23 (12) ◽  
pp. 3390-3396 ◽  
Author(s):  
Rucong Yu ◽  
Jian Li ◽  
Weihua Yuan ◽  
Haoming Chen
Keyword(s):  
Yangtze River ◽  
Rainfall Intensity ◽  
Eastern China ◽  
Late Summer ◽  
Rain Gauge ◽  
Rainfall Amount ◽  
Yangtze River Valley ◽  
River Valley ◽  
The Yangtze River ◽  
Hourly Rainfall

Abstract Using hourly station rain gauge data during 1966–2005, the authors studied changes in the characteristics of the late-summer (July–August) rainfall, which has exhibited a so-called southern flooding and northern drought (SFND) pattern over eastern China in recent decades. Although the rainfall amount and frequency have significantly increased (decreased) in the mid–lower reaches of the Yangtze River valley (North China) during this period, the rainfall intensity has decreased (increased). This finding differs from previous results based on daily data, which showed that the rainfall intensity has increased in the mid–lower reaches of the Yangtze River valley. In this region, the mean rainfall hours on rainy days have increased because of the prolonged rainfall duration, which has led to an increased daily rainfall amount and to a decreased hourly rainfall intensity. Results also show that the SFND pattern is mostly attributed to changes in precipitation with moderate and low intensity (≤10 mm h−1), which contributes 65% (96%) of rainfall amount to the “flooding” (“drought”) in the mid–lower reaches of the Yangtze River valley. Neither frequency nor amount of strong intensity (>20 mm h−1) rainfall exhibits the SFND pattern.

scholarly journals Spatial and Temporal Distribution of Air Temperature in the Northern Hemisphere

2013 ◽  
Vol 6 (3) ◽  
pp. 177-182
Keyword(s):  
Time Series ◽  
20Th Century ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Temporal Distribution ◽  
Surface Air Temperature ◽  
Temperature Time Series ◽  
Mean Values ◽  
The Mean ◽  
Temperature Time

In the present study, the spatial and temporal surface air temperature variability for the Northern Hemisphere has been examined, for the period 1900-1996. Factor Analysis has been applied to 5o Latitude x 10o Longitude grid box data covering the area from almost the equator to 70o N. These data are anomalies of the mean annual air temperature from the respective mean values of the period 1961- 1990. The analysis showed that, mainly 20 regions were determined in the Northern Hemisphere with significantly covariant air temperature time series. The comparison of the trends of the mean annual surface air temperature time series of these regions, revealed such common characteristics as the minimum of the first decade of the 20th century and the recent years warming. The results of this study are also compared to the respective results of a former study in which data for the last half of the century (1948-1996) have been analyzed. The findings extracted indicate the stability of climate distribution in Northern Hemisphere during the 20th century.

Trend of Surface Air Temperature in Eastern China and Associated Large-Scale Climate Variability over the Last 100 Years

2014 ◽  
Vol 27 (12) ◽  
pp. 4693-4703 ◽  
Author(s):  
Ping Zhao ◽  
Phil Jones ◽  
Lijuan Cao ◽  
Zhongwei Yan ◽  
Shuyao Zha ◽  
...  
Keyword(s):  
Air Temperature ◽  
Large Scale ◽  
Eastern China ◽  
Surface Air Temperature ◽  
Tropical Indian Ocean ◽  
Population Data ◽  
Warming Trend ◽  
Climate Indices ◽  
The Past ◽  
Linear Trends

Abstract Using the reconstructed continuous and homogenized surface air temperature (SAT) series for 16 cities across eastern China (where the greatest industrial developments in China have taken place) back to the nineteenth century, the authors examine linear trends of SAT. The regional-mean SAT over eastern China shows a warming trend of 1.52°C (100 yr)−1 during 1909–2010. It mainly occurred in the past 4 decades and this agrees well with the variability in another SAT series developed from a much denser station network (over 400 sites) across this part of China since 1951. This study collects population data for 245 sites (from these 400+ locations) and split these into five equally sized groups based on population size. Comparison of these five groups across different durations from 30 to 60 yr in length indicates that differences in population only account for between 9% and 24% of the warming since 1951. To show that a larger urbanization impact is very unlikely, the study additionally determines how much can be explained by some large-scale climate indices. Anomalies of large-scale climate indices such as the tropical Indian Ocean SST and the Siberian atmospheric circulation systems account for at least 80% of the total warming trends.

scholarly journals On the scaling effect in global surface air temperature anomalies

2013 ◽  
Vol 13 (10) ◽  
pp. 5243-5253 ◽  
Author(s):  
C. A. Varotsos ◽  
M. N. Efstathiou ◽  
A. P. Cracknell
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Air Temperature ◽  
Land Surface ◽  
Surface Air Temperature ◽  
Sea Surface ◽  
Scaling Exponents ◽  
Mean Values ◽  
Temperature Anomalies ◽  
Air Temperature Anomalies

Abstract. The annual and the monthly mean values of the land-surface air temperature anomalies from 1880–2011, over both hemispheres, are used to investigate the existence of long-range correlations in their temporal evolution. The analytical tool employed is the detrended fluctuation analysis, which eliminates the noise of the non-stationarities that characterize the land-surface air temperature anomalies in both hemispheres. The reliability of the results obtained from this tool (e.g., power-law scaling) is investigated, especially for large scales, by using error bounds statistics, the autocorrelation function (e.g., rejection of its exponential decay) and the method of local slopes (e.g., their constancy in a sufficient range). The main finding is that deviations of one sign of the land-surface air temperature anomalies in both hemispheres are generally followed by deviations with the same sign at different time intervals. In other words, the land-surface air temperature anomalies exhibit persistent behaviour, i.e., deviations tend to keep the same sign. Taking into account our earlier study, according to which the land and sea surface temperature anomalies exhibit scaling behaviour in the Northern and Southern Hemisphere, we conclude that the difference between the scaling exponents mainly stems from the sea surface temperature, which exhibits a stronger memory in the Southern than in the Northern Hemisphere. Moreover, the variability of the scaling exponents of the annual mean values of the land-surface air temperature anomalies versus latitude shows an increasing trend from the low latitudes to polar regions, starting from the classical random walk (white noise) over the tropics. There is a gradual increase of the scaling exponent from low to high latitudes (which is stronger over the Southern Hemisphere).

A relation between extreme precipitation and surface air temperature over Russia in the last four decades

2021 ◽  
Author(s):  
Maria Aleshina ◽  
Vladimir Semenov ◽  
Alexander Chernokulsky
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Extreme Precipitation ◽  
Surface Air Temperature ◽  
Precipitation Extremes ◽  
Convective Precipitation ◽  
Temperature Range ◽  
Precipitation Temperature ◽  
Moisture Availability ◽  
Precipitation And Temperature

<p>Precipitation extremes are widely thought to intensify with the global warming due to exponential growth, following the Clausius-Clapeyron (C-C) equation of atmosphere water holding capacity with rising temperatures. However, a number of recent studies based on station and reanalysis data for the contemporary period showed that scaling rates between extreme precipitation and temperature are strongly dependent on temperature range, region and moisture availability. Here, we examine the scaling between daily precipitation extremes and surface air temperature over Russian territory for the last four decades using meteorological stations data and ERA-Interim reanalysis. The precipitation-temperature relation is examined for total precipitation amount and, separately, for convective and large-scale precipitation types. In winter, a general increase of extreme precipitation of all types according to C-C relation is revealed. For the Russian Far East region, the stratiform precipitation extremes scale with surface air temperature following even super C-C rates, about two times as fast as C-C. However, in summer we find a peak-like structure of the precipitation-temperature scaling, especially for the convective precipitation in the southern regions of the country. Being consistent with the C-C relationship, extreme precipitation peaks at the temperature range between 15 °C and 20 °C. For the higher temperatures, the negative scaling prevails. Furthermore, it was shown that relative humidity in general decreases with growing temperature in summer. Notably, there appears to be a temperature threshold in the 15-20 °C range, beyond that relative humidity begins to decline more rapidly. This indicates that moisture availability can be the major factor for the peak-shaped relationship between extreme precipitation and temperature revealed by our analysis.</p>

Twentieth-Century Surface Air Temperature over China and the Globe Simulated by Coupled Climate Models

2006 ◽  
Vol 19 (22) ◽  
pp. 5843-5858 ◽  
Author(s):  
Tianjun Zhou ◽  
Rucong Yu
Keyword(s):  
Climate Change ◽  
Twentieth Century ◽  
Air Temperature ◽  
Climate Models ◽  
Eastern China ◽  
Surface Air Temperature ◽  
Future Climate Change ◽  
Intergovernmental Panel ◽  
Coupled Climate Models ◽  
Anthropogenic Forcings

Abstract This paper examines variations of the surface air temperature (SAT) over China and the globe in the twentieth century simulated by 19 coupled climate models driven by historical natural and anthropogenic forcings. Most models perform well in simulating both the global and the Northern Hemispheric mean SAT evolutions of the twentieth century. The inclusion of natural forcings improves the simulation, in particular for the first half of the century. The reproducibility of the SAT averaged over China is lower than that of the global and hemispheric averages, but it is still acceptable. The contribution of natural forcings to the SAT over China in the first half of the century is not as robust as that to the global and hemispheric averages. No model could successfully produce the reconstructed warming over China in the 1920s. The prescribed natural and anthropogenic forcings in the coupled climate models mainly produce the warming trends and the decadal- to interdecadal-scale SAT variations with poor performances at shorter time scales. The prominent warming trend in the last half of the century over China and its acceleration in recent decades are weakly simulated. There are discrepancies between the simulated and observed regional features of the SAT trend over China. Few models could produce the summertime cooling over the middle part of eastern China (27°–36°N), while two models acceptably produce the meridional gradients of the wintertime warming trends, with north China experiencing larger warming. Limitations of the current state-of-the-art coupled climate models in simulating spatial patterns of the twentieth-century SAT over China cast a shadow upon their capability toward projecting credible geographical distributions of future climate change through Intergovernmental Panel on Climate Change (IPCC) scenario simulations.

Subseasonal Variation in ENSO-Related East Asian Rainfall Anomalies during Summer and Its Role in Weakening the Relationship between the ENSO and Summer Rainfall in Eastern China since the Late 1970s

2011 ◽  
Vol 24 (9) ◽  
pp. 2271-2284 ◽  
Author(s):  
Hong Ye ◽  
Riyu Lu
Keyword(s):  
Eastern China ◽  
Late Summer ◽  
Summer Rainfall ◽  
Rainfall Anomaly ◽  
Precipitation Anomaly ◽  
Early Summer ◽  
Huai River ◽  
Rainfall Anomalies ◽  
Circulation Anomalies ◽  
The Relationship

Abstract The findings of the study reported in this paper show that, during ENSO decaying summers, rainfall and circulation anomalies exhibit clear subseasonal variation. Corresponding to a positive (negative) December–February (DJF) Niño-3.4 index, a positive (negative) subtropical rainfall anomaly, with a southwest–northeast tilt, appears in South China and the western North Pacific (WNP) in the subsequent early summer (from June to middle July) but advances northward into the Huai River Basin in China as well as Korea and central Japan in late summer (from late July to August). Concurrently, a lower-tropospheric anticyclonic anomaly over the WNP extends northward from early to late summer. The seasonal change in the basic flows, characterized by the northward shift of the upper-tropospheric westerly jet and the WNP subtropical high, is suggested to be responsible for the differences in the above rainfall and circulation anomalies between early and late summer by inducing distinct extratropical responses even under the almost identical tropical forcing of a precipitation anomaly in the Philippine Sea. A particular focus of the study is to investigate, using station rainfall data, the subseasonal variations in ENSO-related rainfall anomalies in eastern China since the 1950s, to attempt to examine their role in weakening the relationship between the ENSO and summer mean rainfall in eastern China since the late 1970s. It is found that the ENSO-related rainfall anomalies tend to be similar between early and late summer before the late 1970s, that is, the period characterized by a stronger ENSO–summer mean rainfall relationship. After the late 1970s, however, the anomalous rainfall pattern in eastern China is almost reversed between early and late summer, resulting accordingly in a weakened relationship between the ENSO and total summer rainfall in eastern China.

scholarly journals A Method to Linearly Evaluate Rainfall Frequency–Intensity Distribution

2014 ◽  
Vol 53 (4) ◽  
pp. 928-934 ◽  
Author(s):  
Jian Li ◽  
Rucong Yu
Keyword(s):  
Intensity Distribution ◽  
Eastern China ◽  
High Surface ◽  
Monsoon Circulation ◽  
Intense Rainfall ◽  
Linear Pattern ◽  
Rainfall Frequency ◽  
Hourly Rainfall ◽  
Two Parameters ◽  
Frequency Intensity

AbstractThis study presents a method to linearly evaluate the rainfall frequency–intensity distribution, which is an important component of climatological rainfall characteristics. To grasp and represent the key information of the rainfall frequency distribution by intensity, a two-parameter double exponential function is formulated and fitted to the hourly rainfall observation at each station. The values of the two parameters are estimated by transforming the distribution to a linear pattern. The two parameters determine the location and shape of the fitted distribution curve, and they have different modulating effects in different intensity categories, one governing the low-intensity section and the other dominating the intense rainfall. Through analysis of the estimated parameters, essential features of rainfall distribution can be obtained and assessed. The proposed method is applied to analyze the climatology and long-term variation of the late-summer rainfall in China. It is found that topography and monsoon circulation are two major factors controlling the rainfall frequency–intensity distribution. At stations with high surface altitudes and complex orography, the frequency of light rain is extremely high and the number of intense rainfall events is relatively small. In the plain areas of eastern China, especially those influenced by the main monsoon rain belt, heavy rainfall is more frequent. By tracking the displacement of the parameter pairs, the decadal changes in rainfall frequency–intensity distribution can be clearly visualized and evaluated on a plane constructed by the two parameters. The southern flooding and northern drought pattern can be attributed to the changes in light and moderate rainfall, while the intense rainfall exhibits opposite trends.

scholarly journals Physical Processes of Summer Extreme Rainfall Interannual Variability in Eastern China. Part I: Observational Analysis

2021 ◽  
Author(s):  
Fangxing Tian ◽  
Sihan Li ◽  
Buwen Dong ◽  
Nicholas P Klingaman ◽  
Nicolas Freychet ◽  
...  
Keyword(s):  
Interannual Variability ◽  
Extreme Precipitation ◽  
Southern China ◽  
Asian Summer Monsoon ◽  
Eastern China ◽  
Extreme Rainfall ◽  
Total Precipitation ◽  
Westerly Jet ◽  
North Eastern ◽  
June July

Abstract Extreme precipitation can have catastrophic effects in China by triggering floods, landslides, and other natural disasters. We measure extreme precipitation over eastern China by the seasonal maximum of total precipitation over 5 consecutive days (Rx5day) in June, July, and August (JJA), which contributes more than 20% of the climate mean of JJA regional total precipitation. Based on the empirical orthogonal teleconnection (EOT) method, this work identifies four dominant regions of observed Rx5day interannual variability in eastern China: north-eastern China (EOT1), the southern lower reaches of the Yangtze valley (EOT2), southern China (EOT3) and the northern lower reaches of the Yangtze valley (EOT4). EOT1 extreme precipitation is related to a strong East Asian Summer Monsoon (EASM), a weak monsoon front and a northward displaced upper-tropospheric westerly jet. EOT2 and EOT4 extreme precipitation are located to the south and north of the lower reaches of the Yangtze valley, respectively. They are related to an enhanced and stable monsoon front and a strong western North Pacific subtropical high (WNPSH). The WNPSH associated with EOT4 is stronger than that associated with EOT2, which pushes the monsoon front further north. EOT3 represents extreme precipitation in southern China, related to anomalous southerlies around the western ridge of the WNPSH. The southerlies transport warm and moist air to southern China and increase precipitation there. The four key regions and the related mechanisms are not sensitive to the EOT technique, as the EOT-based extreme precipitation patterns and circulation anomalies are confirmed using Self-Organising Maps (SOMs).

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