Changes in rainfall seasonality pattern over India

Rai, P.; Dimri, A. P.

doi:10.1002/met.1823

Cited by 14 publications

(6 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar decreasing trends were reported by Paul et al [73]. However, few previous studies have reported an increasing trend in rainfall over central India across different time frames [74,75]. Despite the decreasing rainfall trends, the major proportion of the area showed greening over central India, which might be due to government initiatives related to water conservation measures, afforestation and declines in the rate of deforestation, as revealed by Reddy et al [76].…”

Section: Discussionsupporting

confidence: 75%

Resilience of the Central Indian Forest Ecosystem to Rainfall Variability in the Context of a Changing Climate

et al. 2021

View full text Add to dashboard Cite

Understanding the spatio-temporal pattern of natural vegetation helps decoding the responses to climate change and interpretation on forest resilience. Satellite remote sensing based data products, by virtue of their synoptic and repetitive coverage, offer to study the correlation and lag effects of rainfall on forest growth in a relatively longer time scale. We selected central India as the study site. It accommodates tropical natural vegetation of varied forest types such as moist and dry deciduous and evergreen and semi-evergreen forests that largely depend on the southwest monsoon. We used the MODIS derived NDVI and CHIRPS based rainfall datasets from 2001 to 2018 in order to analyze NDVI and rainfall trend by using Sen’s slope and standard anomalies. The study observed a decreasing rainfall trend over 41% of the forests, while the rest of the forest area (59%) demonstrated an increase in rainfall. Furthermore, the study estimated drought conditions during 2002, 2004, 2009, 2014 and 2015 for 98.2%, 92.8%, 89.6%, 90.1% and 95.8% of the forest area, respectively; and surplus rainfall during 2003, 2005, 2007, 2011, 2013 and 2016 for 69.5%, 63.9%, 71.97%, 70.35%, 94.79% and 69.86% of the forest area, respectively. Hence, in the extreme dry year (2002), 93% of the forest area showed a negative anomaly, while in the extreme wet year (2013), 89% of forest cover demonstrated a positive anomaly in central India. The long-term vegetation trend analysis revealed that most of the forested area (>80%) has a greening trend in central India. When we considered annual mean NDVI, the greening and browning trends were observed over at 88.65% and 11.35% of the forested area at 250 m resolution and over 93.01% and 6.99% of the area at 5 km resolution. When we considered the peak-growth period mean NDVI, the greening and browning trends were as follows: 81.97% and 18.03% at 250 m and 88.90% and 11.10% at 5 km, respectively. The relative variability in rainfall and vegetation growth at five yearly epochs revealed that the first epoch (2001–2005) was the driest, while the third epoch (2011–2015) was the wettest, corresponding to the lowest vegetation vigour in the first epoch and the highest in the third epoch during the past two decades. The study reaffirms that rainfall is the key climate variable in the tropics regulating the growth of natural vegetation, and the central Indian forests are dominantly resilient to rainfall variation.

show abstract

Section: Discussionsupporting

confidence: 75%

Resilience of the Central Indian Forest Ecosystem to Rainfall Variability in the Context of a Changing Climate

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Trend of rainfall seasonality of different stations are given in Table . 3 and Figure 8). (Kumar et al, 2014) and India (Rai and Dimri, 2019). If mean rainfall regime occurred every year, SIm would equal to SImi and timing of rainfall peaks and troughs would be same each year (Walsh and Lawler, 1981).…”

Section: Resultsmentioning

confidence: 99%

Onset, Cessation, and Seasonality of Rainfall during Monsoon in Gujarat State of India

Lunagaria

VİJAYAKUMAR²,

CHAUDHARİ

et al. 2022

International Journal of Environment and Geoinformatics

View full text Add to dashboard Cite

Rainfall onset, cessation and its temporal rainfall distribution is very important for monsoon based crop production. Climatic timeseries data of 26 stations of Gujarat state were chosen for the study. Year wise agroclimatic onset, cessation, length, and seasonality of rainy season were determined. Long term average over the timeseries were considered as climatic normals to characterize rainfall pattern to support kharif crop production. Onset starts in South Gujarat from 8th June and it cover the entire state by 6th July at Kutch, with large variation. Cessation of rainy season ranges from 6th September to 21st September in Gujarat. Length of active rainy season prevails from 66 days (at Bhachau) to 96 days (at Ubharat) with state mean of 81 days. Most part of the state has seasonal rainfall regime with dry periods. Rainfall seasonality monsoon season in Gujarat has not changed significantly during recent past.

show abstract

“…noted that the mean of the individual seasonality index ( SI i ) for all individual years will be higher than SI as there will be significant year-to-year noise in monthly rainfall (Rai and Dimri 2020). In absence of these noises, the SI/SI i ratio will be close to 1 and it will be easier to replicate the individual year conditions from the average condition.…”

Section: Indices For Investigating Seasonality Of Rainfallmentioning

confidence: 99%

“…In absence of these noises, the SI/SI i ratio will be close to 1 and it will be easier to replicate the individual year conditions from the average condition. This SI/SI i ratio is thus regarded as replicability index (RI) and can be a useful measure to reckon the inter-annual variations in rainfall (Rai and Dimri 2020;Sharma and Singh 2019;Walsh and Lawler 1981).…”

Section: Indices For Investigating Seasonality Of Rainfallmentioning

confidence: 99%

Spatiotemporal assessment of precipitation variability, seasonality, and extreme characteristics over a Himalayan catchment

Swain

Mishra

Pandey

et al. 2021

Theor Appl Climatol

View full text Add to dashboard Cite

This paper presents a detailed spatiotemporal analysis of the rainfall variability, seasonality, and the extreme characteristics of Tehri catchment located in the lower Himalayan region in India. To this end, the daily rainfall data is extracted from 22 grids for 117 years from the high-resolution (0.25° × 0.25°) gridded observation dataset. Monthly rainfall distribution is evaluated using precipitation concentration index (PCI) and seasonality index. The extreme rainfall indices, viz., maximum 1-day rainfall (Rx1Day), maximum 5-day rainfall (Rx5Day), number of rainy days (NxRainy), total precipitation in rainy days (PRCPTOT), number of heavy rainfall events (NxHeavy), maximum consecutive wet days (CWD), and simple daily intensity index (SDII) are computed for each year considering the thresholds suggested by India Meteorological Department (IMD). The Mann-Whitney-Pettitt test when applied to the annual rainfall time series revealed the year 1958 to be the statistically significant change point. The non-parametric modified Mann-Kendall and Sen's slope tests are employed to detect the trend in monthly, seasonal, annual rainfall time series, extreme precipitation indices, and seasonality indices for both the pre-and post-1958 periods. The annual rainfall over the grids mostly possessed higher negative trends during 1959-2017 than those during 1901-1958, mainly due to the decreasing trends in post-monsoon and winter seasons. Compared to 1901-1958, NxRainy, CWD, and PRCPTOT exhibited a remarkable decreasing trend whereas NxHeavy, Rx1Day, Rx5Day, and SDII exhibited higher positive trends during 1959-2017, indicating intensification of precipitation. The precipitation over the catchment has been more concentrated in the latter epochs of monsoon season and annual rainfall and it is also evident from the increasing trends of the seasonality indices. There is no such study dealing comprehensively with identification of extreme characteristics, seasonality/concentration characteristics, and various categorical trends of precipitation in a Himalayan region reported in literature. This study will be useful in understanding the decreasing trend of precipitation volume coupled with increasing intensity and concentration and it is quite critical for a Himalayan catchment.

show abstract

Changes in rainfall seasonality pattern over India

Cited by 14 publications

References 21 publications

Resilience of the Central Indian Forest Ecosystem to Rainfall Variability in the Context of a Changing Climate

Resilience of the Central Indian Forest Ecosystem to Rainfall Variability in the Context of a Changing Climate

Onset, Cessation, and Seasonality of Rainfall during Monsoon in Gujarat State of India

Spatiotemporal assessment of precipitation variability, seasonality, and extreme characteristics over a Himalayan catchment

Contact Info

Product

Resources

About