Variability and trend of diurnal temperature range in China and their relationship to total cloud cover and sunshine duration

X Xia

doi:10.5194/angeo-31-795-2013

Abstract

Abstract. This study aims to investigate the effect of total cloud cover (TCC) and sunshine duration (SSD) in the variation of diurnal temperature range (DTR) in China during 1954–2009. As expected, the inter-annual variation of DTR was mainly determined by TCC. Analysis of trends of 30-year moving windows of DTR and TCC time series showed that TCC changes could account for that of DTR in some cases. However, TCC decreased during 1954–2009, which did not support DTR reduction across China. DTRs under sky conditions such as clear, cloudy and overcast showed nearly the same decreasing rate that completely accounted for the overall DTR reduction. Nevertheless, correlation between SSD and DTR was weak and not significant under clear sky conditions in which aerosol direct radiative effect should be dominant. Furthermore, 30–60% of DTR reduction was associated with DTR decrease under overcast conditions in south China. This implies that aerosol direct radiative effect appears not to be one of the main factors determining long-term changes in DTR in China.

Highlights

The outstanding feature was that both DTR and total cloud cover (TCC) showed a decreasing trend in all regions
The DTR reduction in spring and in north China was generally larger than that in summer and in south China. This feature is in agreement with the results of Zhou et al (2010) who pointed out that the magnitude of the decreasing DTR trend decreased with increasing precipitation amount and cloud cover
Annual DTR and TCC decreased by 0.14◦ and 0.69 % per decade during 1954–2009, respectively

Summary

Introduction

T0na.h1le8te◦amCnpnfeurroaamltua1rve9e0rra6angtgeoe2g(0Dlo0Tb5Ra(lI)PwtCeamCsp,oMe2br0sa0oetur7dvr)ee.edHiltnoocwDGrdeeeevaecesvreroe,deatsshle0eoc.s7dipie4inumcn±re-teifnicttdfDhauTceceRe2sd0awttnhhedelclsoeubnvruetfutraarcuyleln(2ds2o0e0ltraChers3ctrMeiamnd)Mtaiuatsrethyoidoowdwnthaee(erSdmlSdtiDRhenGca)gate.edoTtvhavohleeeisrssvelgalocarlDmoiicpiaebsoktcmaidnuoilensnltlesassdiinfoenriidnecncstpastdruhoare--l the 1950s over most global land areas due to a lower rate variability in the model-calculated DTR and SSR could have of warming in maximum temperature than in minimum tem- various origins (Wild, 2009a). An obvious origin could be peratures (Karl et al, 1993; Zhou et al, 2H00y4d). RCololoudgayndanda missing increasing trend in the mHodyedledroclloougd ychaarancdterisprecipitation portant role inarethewiwdeolryldswuigdgeesDteTdRtoredhuacvteiEopnlaadyruetehd taoSntyhimesir-temtriecssu,lstufcrhomas cloud cover and cloud a poor representation oaflEbceoadmor,ptwhlehxiScaheyrcososutoelld–mlcilkoeulyd significant effects on the surface energy and hydSrolcoigeicnalces. X. Xia: Variability and trend of diurnal temperature range in China Latitude (oN) NEC NWC 40 NCP TLP 35

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Discussion

Conclusion