Insights on Satellite-Based IMERG Precipitation Estimates at Multiple Space and Time Scales for a Developing Urban Region in India

Regonda, Satish Kumar (2023) Insights on Satellite-Based IMERG Precipitation Estimates at Multiple Space and Time Scales for a Developing Urban Region in India. JOURNAL OF HYDROMETEOROLOGY, 24 (6). pp. 977-996. ISSN 1525-7541

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Abstract

Satellite-based rainfall estimates are a great resource for data-scarce regions, including urban regions, be-cause of its finer resolution. Integrated Multi-satellitE Retrievals for GPM (IMERG) is a widely used product and is evaluated at a city scale for the Hyderabad region using two different ground truths, i.e., India Meteorological Department (IMD) gridded rainfall and Telangana State Development Planning Society (TSDPS) automatic weather station (AWS) measured rainfall. The IMERG rainfall estimates are evaluated on multiple spatial and temporal scales as well as on a rainfall event scale. Both continuous and categorical verification metrics suggest good performance of IMERG on the daily scale; how-ever, relatively decreased performance was observed on the hourly scale. Underestimated and overestimated IMERG esti-mates with respect to IMD gridded rainfall and AWS measured rainfall, respectively, suggest the performance depends on type of ground truth. Unlike categorical metrics, RMSE and PBIAS have a pattern implying a systematic error with respect to rainfall amount. Further, sample size, diurnal variations, and season are found to have a role in IMERG estimates' perfor-mance. Temporal aggregation of hourly to daily time scales showed the improved IMERG performance; however, no spatial -scale dependence was observed among zonewise and Hyderabad region-wise rainfall estimates. Comparison of raw and bias-corrected IMERG rainfall-based intensity-duration-frequency (IDF) curves with corresponding hourly rain gauge IDF curves showcases the value addition via simple bias correction techniques. Overall, the study suggests the IMERG estimates can be used as an alternative data source, and it can be further improved by modifying the retrieval algorithm.

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IITH Creators:

IITH Creators	ORCiD
Regonda, Satish Kumar	http://www.orcid.org/0000-0003-3188-9415

Item Type:

Article

Uncontrolled Keywords:

GPM IMERG; HYDROLOGICAL UTILITY BIAS CORRECTION; RAINFALL; PRODUCTS; IMPACT; TRMM; MICROWAVE; MONSOON; TMPA; Rainfall; Hydrometeorology; Automatic weather stations; Remote sensing; Satellite observations; Urban meteorology

Subjects:

Civil Engineering
Civil Engineering > Structural engineering and underground construction

Divisions:

Department of Civil Engineering

Depositing User:

Mr Nigam Prasad Bisoyi

Date Deposited:

12 Nov 2023 04:11

Last Modified:

12 Nov 2023 04:56

URI:

http://raiithold.iith.ac.in/id/eprint/11734