Urbanization signature in the observed heavy rainfall climatology over India

Abstract

ABSTRACT:We assess the urbanization impacts on the heavy rainfall climatology during the Indian summer monsoon. While a number of studies have identified the impact of urbanization on local precipitation, a large-scale assessment has been lacking. This relation between urbanization and Indian monsoon rainfall changes is investigated by analyzing in situ and satellite-based precipitation and population datasets. Using a long-term daily rainfall dataset and high-resolution gridded analysis of human population, this study showed a significantly increasing trend in the frequency of heavy rainfall climatology over urban regions of India during the monsoon season. Urban regions experience less occurrences of light rainfall and significantly higher occurrences of intense precipitation compared to nonurban regions. Very heavy and extreme rainfall events showed increased trends over both urban and rural areas, but the trends over urban areas were larger and statistically more significant. Our analysis suggests that there is adequate statistical basis to conclude that the observed increasing trend in the frequency of heavy rainfall events over Indian monsoon region is more likely to be over regions where the pace of urbanization is faster. Moreover, rainfall measurements from satellites also indicate that urban areas are more (less) likely to experience heavier (lighter) precipitation rates compared to those in nonurban areas. While the mechanisms causing this enhancement in rainfall remain to be studied, the results provide the evidence that the increase in the heavy rainfall climatology over the Indian monsoon region is a signature of urban-induced rainfall anomaly.

Variation in the orographic extreme rain events over the Meghalaya Hills in northeast India in the two halves of the twentieth century

“…The effect of urban-induced rainfall was observed in northern Bangladesh (Yamane et al 2010) and urban areas in India (Kishtawal et al 2010;Mitra et al 2012;Vittal et al 2013). Both Shillong (the capital of Meghalaya with a population of 350,000 in 2011) and Gauhati (the capital of Assam with a population of 968,000 in 2011) are two of the most rapidly growing cities in India during the second half of the twentieth century.…”

Sensitivity of the East Asian Summer Monsoon Circulation and Precipitation to an Idealized Large-Scale Urban Expansion

“…Mitra et al (2012) analyzed premonsoonal rainfall over a megalopolis in India and identified the possible association between urban land cover expansion and premonsoonal rainfall increase. Urbanization effects on heavy rainfall during the Indian summer monsoon were assessed by Kishtawal et al (2010) with in situ and satellite-based precipitation. They found a significant increasing trend in the frequency of heavy rainfall over the urban regions of India during the monsoon season.…”

Impacts of Urban Development on Precipitation in the Tropical Maritime Climate of Puerto Rico

“…Although there has been considerable interest in evaluating temperature differences between urban areas and their rural surroundings [3,[9][10][11][12][13][14], studies of variations in long-term precipitation due to urbanization [6,15,16] or other changes in land use and land cover (LULC), such as deforestation/afforestation, are limited [4]. Deforestation can result in albedo increases, reduction of evapotranspiration (which changes sensible and latent heat partitioning), and rainfall interception [15].…”