Changing characteristics of extreme wet and dry spells of Indian monsoon rainfall

Abstract

Modeling of extreme events and its dynamic behavior have always been an intriguing topic. Increase in the magnitude and frequency of extreme events has widely been reported in recent decades, which is attributed to abrupt changes in climate. Numerous studies on extreme Indian monsoon characteristics, using a coarse‐resolution data set, have pointed out significant changes in heavy precipitation pattern over India. However, these studies differ in their conclusions, emphasizing the need for a fine‐resolution analysis. The present study aims to analyze the spatiotemporal variations and trends in the extreme (wet and dry) Indian monsoon precipitation, using 0.25° × 0.25° high‐resolution gridded data for a period of 113 years (1901–2013). Significant increase in the maximum intensity of rainfall and spatial heterogeneity is observed over the past half century. In addition, significant negative trends in wet spell durations and positive trends in dry spell durations are observed over wet regions; whereas contrasting trends are observed over dry regions. A shift in the frequency distribution of extreme events during the monsoon period is also noticed. The 50 year return level of maximum intensity clearly shows positive trends over the past century. Though characteristics of extremes are observed to be highly localized, apparent signs of wet regions turning drier and dry regions turning wetter are obtained. A comprehensive insight into different characteristics (intensity, spell, onset, and frequency) of Indian monsoon extremes is provided, which will help in effective water resources management and flood/drought hazard preparedness.

Southward shift of precipitation extremes over south Asia: Evidences from CORDEX data

“…South Asian region, including the Indian sub-continent, receives most of the precipitation due to monsoon, which is strongly sensitive to climate change [2][3][4][5][6] . The characteristics of Indian Summer Monsoon Rainfall (ISMR) are changing in terms of its trend in extreme precipitation events [7][8][9][10][11][12][13][14][15] . However, most studies do not agree on the nature of the change.…”

“…However, some studies suggest no significant trend in extreme precipitation across India 13 , and dry spell has a positive trend in most parts of India 14 . Vinnarasi et al 15 suggested a significant negative trend in wet spell duration and a positive trend in dry spell duration after analyzing large spatial resolution (0.25° latitude × 0.25° longitude) data set. Moreover, the increasing trend in extreme precipitation during the monsoon season is highly localized and vary spatially.…”

Determining the Start of the Growing Season from MODIS Data in the Indian Monsoon Region: Identifying Available Data in the Rainy Season and Modeling the Varied Vegetation Growth Trajectories

“…In the Indian monsoon region, the growth of vegetation is mainly controlled by precipitation [6,7], which has experienced significant changes in intensity and frequency over the past half-century [8][9][10]; these changes will certainly cause shifts in vegetation phenology, such as a significant advance in the start of growing season (SOS) in northern parts (e.g., Punjab, Haryana) of India [11]. Therefore, accurate depictions of vegetation phenology in the Indian monsoon region are urgently needed.…”

Intercomparison of daily precipitation persistence in multiple global observations and climate models

“…Conversely, [22] documented a significant decreasing trend of annual maximum consecutive dry days (CDD) in Australia. Significant trends with different signs and magnitude regarding the characteristics of dry and wet spell lengths during the 20th century was identified in India [14,23,24]. While these studies show that some regions of the world have experienced significant changes in daily precipitation persistence, a lack of consensus on the metrics used to characterize precipitation persistence makes it difficult to compare the results from different studies.…”