DOI: 10.1007/s00382-012-1414-0
Scopus记录号: 2-s2.0-84869508473
论文题名: On the fog variability over south Asia
作者: Syed F.S. ; Körnich H. ; Tjernström M.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2012
卷: 39, 期: 12 起始页码: 2993
结束页码: 3005
语种: 英语
英文关键词: Fog
; Fog detection
; Inter-annual variability
; South-Asia
; Trend
英文摘要: An increasing trend in fog frequencies over south Asia during winter in the last few decades has resulted in large economical losses and has caused substantial difficulties in the daily lives of people. In order to better understand the fog phenomenon, we investigated the climatology, inter-annual variability and trends in the fog occurrence from 1976 to 2010 using observational data from 82 stations, well distributed over India and Pakistan. Fog blankets large area from Pakistan to Bangladesh across north India from west to east running almost parallel to south of the Himalayas. An EOF analysis revealed that the fog variability over the whole region is coupled and therefore must be governed by some large scale phenomenon on the inter-annual time scale. Significant positive trends were found in the fog frequency but this increase is not gradual, as with the humidity, but comprises of two distinct regimes shifts, in 1990 and 1998, with respect to both mean and variance. The fog is also detected in ERA-Interim 3 hourly, surface and model level forecast data when using the concept of "cross-over temperature" combined with boundary layer stability. This fog index is able to reproduce the regime shift around 1998 and shows that the method can be applied to analyze fog over south Asia. The inter-annual variability seems to be associated with the wave train originating from the North Atlantic in the upper troposphere that when causing higher pressure over the region results in an increased boundary layer stability and surface-near relative humidity. The trend and shifts in the fog occurrence seems to be associated with the gradual increasing trend in relative humidity from 1990 onwards. © 2012 Springer-Verlag. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/55095
Appears in Collections: 过去全球变化的重建
There are no files associated with this item.
作者单位: Department of Meteorology, Stockholm University, 10691 Stockholm, Sweden; Pakistan Meteorological Department, 44000 Islamabad, Pakistan; Department of Meteorology, The Bert Bolin Centre for Climate Research, Stockholm University, 10691 Stockholm, Sweden
Recommended Citation:
Syed F.S.,Körnich H.,Tjernström M.. On the fog variability over south Asia[J]. Climate Dynamics,2012-01-01,39(12)