Wet and dry spell characteristics of global tropical rainfall

Ratan, R and Venugopal, V (2013) Wet and dry spell characteristics of global tropical rainfall. In: WATER RESOURCES RESEARCH, 49 (6). pp. 3830-3841.

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Abstract

In this study, we analyze satellite-based daily rainfall observations to compare and contrast the wet and dry spell characteristics of tropical rainfall. Defining a wet (dry) spell as the number of consecutive rainy (nonrainy) days, we find that the distributions of wet spells appear to exhibit universality in the following sense. While both ocean and land regions with high seasonal rainfall accumulation (humid regions; e. g., India, Amazon, Pacific Ocean) show a predominance of 2-4 day wet spells, those regions with low seasonal rainfall accumulation (arid regions; e. g., South Atlantic, South Australia) exhibit a wet spell duration distribution that is essentially exponential in nature, with a peak at 1 day. The behavior that we observed for wet spells is reversed for the dry spell characteristics. In other words, the main contribution to the dry part of the season, in terms of the number of nonrainy days, appears to come from 3-4 day dry spells in the arid regions, as opposed to 1 day dry spells in the humid regions. The total rainfall accumulated in each wet spell has also been analyzed, and we find that the major contribution to seasonal rainfall for arid regions comes from 1-5 day wet spells; however, for humid regions, this contribution comes from wet spells of duration as long as 30 days. We also explore the role of chance as well as the influence of organized convection in determining some of the observed features.

Item Type:	Journal Article
Publication:	WATER RESOURCES RESEARCH
Publisher:	AMER GEOPHYSICAL UNION
Additional Information:	Copyrright of this article is belongs to AMER GEOPHYSICAL UNION
Keywords:	wet and dry spells; rainfall; universality
Department/Centre:	Division of Mechanical Sciences > Divecha Centre for Climate Change
Date Deposited:	25 Sep 2013 12:00
Last Modified:	25 Sep 2013 12:00
URI:	http://eprints.iisc.ac.in/id/eprint/47322

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