Interannual and Interdecadal Variability of the Number of Cold Days in Hong Kong and Their Relationship with Large-Scale Circulation

Hoffman H. N. Cheung, Wen Zhou, Sai-ming Lee, Hang-wai Tong
2015 Monthly Weather Review  
During the past decade (2004/05-2013/14), the number of cold days in Hong Kong (N CD ), as a proxy of the temperature of southern China, appeared to have increased from the historical minimum, in contrast to a remarkable decline in the entire postwar period. This is related to the recent apparent changes in the largescale circulation upstream and downstream of the East Asian winter monsoon (EAWM) region: the increase in Ural blocking (UB) that enhances cold advection from the polar region and
more » ... polar region and reinforces the Siberian high and the decrease in a western Pacific (WP)-like index that corresponds to increasing meridional gradient of geopotential height over the EAWM region. Overall, UB and WP account for 26.4% of the interannual (#8 yr) variance and 83.7% of the decadal (.8 yr) variance of N CD for the period 1948/49-2013/14, indicating that further study could lead to improvement in the prediction of N CD .
doi:10.1175/mwr-d-14-00335.1 fatcat:ks2qgaaxune23i56wc6xdah3fi