The Hindu Business Line : Weather observation network in Kerala fails to measure up: Study

AN assessment of the weather data observation network in Kerala, the first port of call for the southwest monsoon, has revealed that the existing infrastructure fails to measure up to standards prescribed by the World Meteorological Organisation (WMO).

WMO requirements for observation networks for the tropics, of which Kerala is a part, demand a much denser network that adequately captures the extreme variability of weather in these parts. The WMO model calls for a monitoring equipment to be located every 100 sq km in coastal areas and in the plains, and 50 sq km in elevated geographies (mountains and high ranges).

However, the year-long field study taken up jointly the State Planning Board, the Cochin University of Science and Technology and the Indian Space Research Organisation (ISRO) revealed that the State has only a sprinkling of 30 full-fledged weather stations and 254 rain gauges. This has left a case for setting up an additional 56 weather stations at the least count.

Also, for a State of Kerala's diverse biodiversity, rainfall measurements need to be far more representative than is the case now. At least 400 rain gauge stations need to be installed towards this purpose, against which it has only 254.

Except for the 13 weather observatories of the India Meteorological Department (IMD) and the six automatic weather stations maintained by other agencies, all other data currently generated are received in the `delayed mode' only.

Availability of real time data, which is very crucial for input to forecast models, is very limited.

An analysis of the geographical spread of these stations showed that there are several gaps with only a few districts covered as required by WMO specifications. Ideally, each block area (approximating 100 sq km) needs to have a weather observation facility and each village or a cluster of villages, a rain gauge station.

Thus, while highlighting the inadequacy of the present observation network in terms of station density, the study also brought out in clear terms its inability to make available real time data. A way to work out of this sticky situation was to go for automatic weather stations and automatic rain gauges for new stations being planned. This way, real time data could be had for the asking even as the need for deploying personnel for recording observations is obviated.

Observations generated would also play a crucial role in being a sure-fire indicator to the onset of monsoon over the country. Studies have shown a close correlation between rainfall over the State with the overall performance of monsoon in the country.

Another aspect that needs mention is the concern expressed over possible global climate exchange scenarios and their adverse impact on local weather.

Continuing deforestation coupled with large-scale land cover changes is the root cause for potential climate changes occurring in decadal scales.

The overall impact of such climate change at the local scale will be severe due to the amplification effect of the regional processes such as wind flow, heat transfer, evaporation, land-atmosphere reaction and vegetation cover.

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