Delineation of homogeneous temperature regions: a two-stage clustering approach

Bharath, R and Srinivas, VV and Basu, Bidroha (2016) Delineation of homogeneous temperature regions: a two-stage clustering approach. In: INTERNATIONAL JOURNAL OF CLIMATOLOGY, 36 (1). pp. 165-187.

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Abstract

Homogeneous temperature regions are necessary for use in hydrometeorological studies. The regions are often delineated by analysing statistics derived from time series of maximum, minimum or mean temperature, rather than attributes influencing temperature. This practice cannot yield meaningful regions in data-sparse areas. Further, independent validation of the delineated regions for homogeneity in temperature is not possible, as temperature records form the basis to arrive at the regions. To address these issues, a two-stage clustering approach is proposed in this study to delineate homogeneous temperature regions. First stage of the approach involves (1) determining correlation structure between observed temperature over the study area and possible predictors (large-scale atmospheric variables) influencing the temperature and (2) using the correlation structure as the basis to delineate sites in the study area into clusters. Second stage of the approach involves analysis on each of the clusters to (1) identify potential predictors (large-scale atmospheric variables) influencing temperature at sites in the cluster and (2) partition the cluster into homogeneous fuzzy temperature regions using the identified potential predictors. Application of the proposed approach to India yielded 28 homogeneous regions that were demonstrated to be effective when compared to an alternate set of 6 regions that were previously delineated over the study area. Intersite cross-correlations of monthly maximum and minimum temperatures in the existing regions were found to be weak and negative for several months, which is undesirable. This problem was not found in the case of regions delineated using the proposed approach. Utility of the proposed regions in arriving at estimates of potential evapotranspiration for ungauged locations in the study area is demonstrated.

Item Type:	Journal Article
Publication:	INTERNATIONAL JOURNAL OF CLIMATOLOGY
Publisher:	WILEY-BLACKWELL
Additional Information:	Copy right for this article belongs to the WILEY-BLACKWELL, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA
Keywords:	regionalization; cluster analysis; temperature; hydrometeorology; homogeneous temperature regions; India
Department/Centre:	Division of Mechanical Sciences > Civil Engineering
Date Deposited:	10 Feb 2016 05:51
Last Modified:	10 Feb 2016 05:51
URI:	http://eprints.iisc.ac.in/id/eprint/53201

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