Climatic and Environmental Research 

About: Climatic and Environmental Research is an academic journal. The journal publishes majorly in the area(s): Precipitation & Subtropical ridge. Over the lifetime, 502 publications have been published receiving 2859 citations.

A New Monsoon Index,Its Interannual Variability and Relation with Monsoon Precipitation

Abstract: The normalized seasonality of winds δ presented firstly by Zeng is calculated again by use of new datasets.To consist with the traditional and known definitions from many researchers,we take the region where δ~*=δ-20,i.e,the difference in wind direction between winter and summer is lager than π/2 as monsoon region.The geographical extent of the global monsoons form the method here covers all monsoon regions over the world known so far(however,the domain here is slightly smaller than that from Zeng),especially the tropical monsoons are just included in the region between the positions of the Intertropical Convergence Zone or ITCZ in winter and summer.Then,the interannual variations of areal average δ~*_m of some key monsoons as the broad scale monsoon index proposed by Li and Zeng are analyzed by virtue of the dynamical normalized seasonality(DNS) of winds δ~*_m=δ_m-2(δ_m is similar to δ but depends on year m).The long-term decreasing trends with different extent can be found in the intensities of the South Asian summer monsoon(SASM) and East Asian summer monsoon(EASM) since the mid-1970s,the South China Sea summer monsoon(SCSSM) since 1980s,and the West African summer monsoon(WASM) since 1967,especially the most remarkably weakening in the WASM.Both the West African summer monsoon index(WASMI) and the South Asian summer monsoon index(SASMI) are significant positively correlated with the summer precipitation over the local monsoon regions,respectively,and there is statistical structure in the correlation map between the East Asian summer monsoon index(EASMI) and summer rainfall in China and East Asia,and there exist better statistical correlations over large regions in every Oceans between the South China Sea summer monsoon index(SCSSMI) and summer global rainfall and sea level pressure anomalies.

Changes of Surface Air Temperature in China During 1951—2004

Abstract: A data set from 726 stations was used to analyze surface air temperature change in Mainland China. The data set has been processed more carefully, and the main in-homogeneities existing in the monthly mean temperature data have been checked and corrected. The widely accepted procedures for creating area-averaged climatic time series and for calculating linear trend have been used. Analyses have been made for annual and monthly mean temperature. Annual mean surface air temperature in Mainland China as a whole rose by about 1.3 ℃ for the last 54 years, with a warming rate of about 0.25 ℃/10 a. The warming is more rapid than the average values of the world and the Northern Hemisphere. The most evident warming occurred in winter and spring as expected. Northeast China, North China and Northwest China experienced more significant warming in terms of annual mean temperature, while a cooling trend for southwestern China reported in earlier studies is still continuing. Summer mean temperature in the middle and lower reaches of the Yangtze River also decreased in the last 55 years. We have also tentatively analyzed the possible causes for the observed change in temperature.

Reanalysis of Surface Air Temperature Change of the Last 100 Years over China

Abstract: The present paper gives a new country-averaged surface air temperature anomaly series for China for 1905—2001 period We used monthly mean temperature dada obtained by averaging monthly mean maximum and minimum temperatures to avoid the in-homogeneity problems with data induced by differential observation times and statistic methods between early and late 20th century The widely accepted procedures for creating area-averaged climatic time series and for calculating linear trend have been used The new air temperature time series has been analyzed and its rationality also has been explained The result shows that annual mean surface air temperature of the country for the past 97 years experienced a warming of 079 ℃, with a warming rate of 008 ℃/10 a which is slightly larger than global or northern hemispheric average as given by IPCC TAR Two warm periods, which occurred respectively in the 1930s—1940s and the 1980s—1990s, are evident, with 1946 and 1998 as the warmest ones within the record period It is interesting to note that the temperature anomalies of the 1990s are no higher than those of the 1940s, implying the larger contribution from warming of the cold periods to the long-term positive trend Seasonal features of temperature changes for the last 97 years are characterized by the more rapid warming of wintertime and springtime, with summer showing an insignificant cooling trend during the 97-year period However, the reanalysis did not take account for urbanization effect on temperature record It is essential to pay more attention to the problem in the further study if we intend to better detect the regional change in climate

Recent Progresses in Studies of Regional Temperature Changes in China

Abstract: A brief summary of some recent major research findings of temperature changes over China is made in this paper The findings come mainly from studies on observed changes of surface air temperature of the last 55 years, 100 years and 1 000 years, and of free atmospheric temperature of the last 50 years, on attribution of surface air temperature change to anthropogenic forcing, and on effect of rapid urbanization on site temperature records and regional average temperature series Based on a data set of national basic and reference stations, which have been quality-controlled and adjusted for in-homogeneity dominantly induced by relocation of stations, updated surface air temperature time series of the past 55 years and 100 years are established The new temperature series show a generally more rapid warming than those obtained before, with the rates of change of annual mean temperature reaching 022 ℃/10 a and 008 ℃/10 a respectively for the past 55 year and 100 years The current warming is more significant in Northeast China, North China, Northwest China and the Tibetan Plateau, and the largest increase in temperature occurs in wintertime and springtime The warming of the last 55 years is the result of more obvious rising of mean minimum temperature The same change has happened for the country averaged annual extreme low temperature, while the annual extreme high temperature only experiences an insignificant rise The frequency of temperature-related extreme events such as cold wave, cool summer, hot days generally tends to decrease or to be unchanged in the country as a whole It is found, however, that significant effects of urbanization on recorded trends of temperature for single stations as well as for region averaged temperature series exist in a few regions investigated so far In North China which experiences the most remarkable warming in the country, increase of annual mean temperature induced by urbanization for national basic and reference stations reaches 044 ℃ in period of 1961—2000, with an increasing rate of temperature of 011 ℃/10 a, accounting for 38% of the total warming rate as recorded by these stations The effects of urbanization might have remained in the other regional changes in annual mean temperature Regardless the remarkable warming of the surface, mid-to lower troposphere (850—400 hPa) witnesses no significant change in temperature, with a rate of change of only 005 ℃/10 a for the period of 1961—2004, and upper troposphere (300—150 hPa) and lower stratosphere (100—50 hPa) are experiencing a significant decrease in temperature at rates of -017 ℃/10a and -022 ℃/10 a respectively A slight decrease in temperature is found for the entire troposphere in the period investigated However, mid-to lower troposphere temperature is increasing in the past 20 years at a much higher rate than before, and the difference of change between surfaces and mid-to lower troposphere is getting smaller A preliminary temperature series of the past 1 000 years has been reconstructed mainly based on tree ring data in the west and historical record in the east It shows the warmth of period corresponding to the Medieval Warm Period (MWP) and the marked coldness of the Little Ice Age last from about 1400 to 1900 The warmth of the MWP, however, seems not so evident in the country as a whole as reported before, though the temperature in the end of 11th century and in the mid 13th century might have been higher than that of any decade of 20th century It is still premature to answer the question of what cause the observed warming on the surface in China Some evidence support the claim that it has mainly been induced by the increased concentration of greenhouse gases in atmosphere, but the influences of other factors like solar activities and the low-frequency oscillations of ocean-atmospheric system could not be ruled out at present

Severe Snow and Freezing-Rain in January 2008 in the Southern China

Abstract: The severe snow and freezing-rain in January 2008 affected the Southern China.The heavy snow storm mainly occurred in the Yangtze and Huaihe River Valleys,and the freezing-rain affected from Guizhou,Hunan,Jiangxi to Zhejiang Provinces.The damage that the storm caused was very serious,with the economic losses of about 151.65 billion Yuan,and particularly the damage of power delivery infrastructure in the Southern China.The atmospheric processes associated with the storm are analyzed.During the storm period,a large blocking circulation system stayed over the Asian continent with a blocking high pressure to the north of the Lake Baikal and a cut-off low near the Caspian Sea.There was a strong jet stream in the upper troposphere extending from the Mediterranean Sea,Tibetan Plateau,South China to the southern part of Japan.The blocking circulation system lasted for 22 days.During the storm period there was a quasi-stationary front in the Southern China with a frontal zone extending from the coast of South China in the lower troposphere to the Yangtze and Huaihe River Valley in the middle troposphere.At that time,cold air was shifted southward at low levels leading to a cold air damming.At mid-levels(850-200 hPa),a southerly flow advected warm and moist air from the South China Sea,forming a melting layer(t0 ℃) in the Southern China which is a necessary condition for the formation of freezing-rain.There was a long-lived developing Rossby wave packet along the jet stream over the Southern Asia leading to the formation of a trough(at 85°E) and ridge(at 135°E) pair over the Southern China,enhancing the advection of warm and moist air in the Southern China.These meteorological conditions are commonly associated with winter snow and ice storms in the Southern China.During the storm period there were regions of cyclonic potential vorticity which advected from the cut-off low near the Caspian Sea along the jet stream over the Tibetan Plateau downstream to the quasi-stationary front in the Southern China on 16-22 January,25-29 January and 30 January-2 February 2008,respectively.The advection of cyclonic potential vorticity to the frontal zone is a favorable condition for the frontgenesis of the stationary front in the Southern China,leading to heavy snow and severe freezing-rain in January 2008 in Southern China.