The global monsoon definition using the difference of local minimum and maximum pentad precipitation rates associated with cross-equatorial flow reversal

Abstract

Since most previous attempts to establish monsoon indices have been limited to specific regions, they have lacked the applicability to universally describe the global monsoon domain. In this paper, we first review the history of global monsoon study and then identify the climatology of global precipitation associated with major systems of the atmospheric general circulation. A new index, based on the annual and semiannual harmonic precipitation rate difference between two local calendar maximal and minimal precipitation pentads, is used to identify the global monsoon domain focusing on where experienced and what caused the climatic dry-wet alteration. The global monsoon domain is defined by the regions where two pentad-mean precipitation difference exceeds 4 mm·day −1 , which is also influenced by the low-level prevailing wind reversal associated with the cross-equatorial flow. This definition not only confirmed previous results of the classical global monsoon domain from the tropical Africa to Asia-Australia and nonclassical monsoon region in the tropical America but also solved an issue of missing local summer monsoon spots.

Examination of Hurricane Sandy’s (2012) structure and intensity evolution from full-field and anomaly-field analyses

“…For the diurnal cycle, the summer lowlevel wind variation was noted in the Southern United States (Crawford and Hudson, 1973) and the rain averaged over southern China is the strongest at late night or in early morning during summer (Yu et al, 2007(Yu et al, , 2009Chen et al, 2009). For the annual cycle, the SCS summer monsoon experiences a rapid climatic transition from a dry stage with easterly wind to a wet stage with westerly wind in middle May for only several days (Qian and Yang, 2000;Qian and Jiang, 2015). Using the GBAM, an experiment indicates that a bias of TC track can be produced by a daily-mean climatological wind or n-day-mean climatological wind at a calendar moment compared to the temporal climatology derived in our approach (figures not shown).…”

Tripole precipitation pattern and SST variations linked with extreme zonal activities of the western Pacific subtropical high

“…A typical northward jump occurs in mid‐July, which indicates the end of mei‐yu (rainy) period along the Yangtze River Valley (YRV) and the beginning of rainy season in North China (Tao and Chen, ; Ding and Chan, ; Yu et al , ). The aforementioned migrations are climatic features of the WPSH activities and rainbelt in summer (Qian et al , ; Wang and Ding, ; Qian and Jiang, ). Nevertheless, the anomalous WPSH activities are the causes of anomalous drought or flood disasters and should be paid more attention.…”