India Water Portal

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About the India Water Portal

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Meteorological data is essential for water resource planning and research. In India, this data is difficult to obtain for the average citizen. In this application, entire datasets for various meteorological indicators from 1901 to 2002 , for any part of India, is made available for users, in a simple format. We foresee that this data can be useful in making rainwater harvesting and water balance estimates, in various research areas, climate change adaptation studies and more. We also believe in the democratising effect of having this kind of data freely available to the general public.

Access the Data

http://www.indiawaterportal.org/data/metdata/

Contents of the Data

Data Source

The database that is used for this work, is the publicly available Climate Research Unit (CRU) TS2.1 dataset, out of the Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia in Norwich, UK. This published dataset consists of interpolated (on a 0.5 degree latitude-longitude grid) global monthly rainfall, temperature, humidity and cloud cover data, from 1901 to 2002 (Mitchell and Jones, 2005).

Processing of the CRU dataset

Typically, large spatiotemporal datasets of this sort require the use of Geographic Information Systems (GIS). For the purpose of converting the CRU dataset from its orginal format, the opensource GIS software GRASS (Geographic Resources Analytical Support System) was used on a Ubuntu Linux operating system. The original datasets, available at http://www.cru.uea.ac.uk/~timm/grid/CRU_TS_2_0.html, were converted into GRASS raster formats. GRASS GIS modules along with Linux scripting were used to extract the monthly average rainfall; maximum, minimum and average temperatures; and vapour pressure (humidity), from 1901 to 2002, for the Indian subcontinent.

The Evapotranspiration data was derived from the weather data using the procedures of the FAO-56 manual (Allen et. al, 1998), referenced at the bottom of this page.