Friday, March 05, 2010

‘Advection' causing mercury to rise over north-west

The India Meteorology Department (IMD) has said that ‘warm air advection' is causing maximum and minimum temperatures to continue to remain appreciably above normal over many parts of northwest and central India.

The net result of warm air advection, a process in which the wind blows from a region of warm air to a region of cooler air, makes the region warmer. This is expected to help the summer clime gradually entrench itself over northwest India.


Explaining the ‘advection' process, experts say wind blows from a region of warm air to a region of cooler air, resulting in a warming of the colder region. As the warm advection persists, temperatures in the colder region begins to increase.

On Thursday, maximum temperatures were above normal over most parts of Rajasthan, many parts of Haryana, Himachal Pradesh, Uttarkhand, Madhya Pradesh, north Chhattisgarh, Orissa, Gangetic West Bengal, Manipur, Tripura, west Uttar Pradesh, Bihar, Vidarbha, Andhra Pradesh, Karnataka, Tamil Nadu and Kerala.

While no significant change is expected in minimum temperatures over northwest India during the next 24 hours, the maximum temperature is expected to fall over northwest India during the next two days due to cloudiness from a prevailing western disturbance.

Meanwhile, the western disturbance of moderate intensity lay parked over the western Himalayan region with an induced upper air cyclonic circulation over central Rajasthan. Coming close on its heels is a fresh westerly system, which will impact both western Himalayas and Punjab around Saturday.

Strong northwesterly to westerly winds are prevailing over Gangetic plains in the lower levels.

Satellite imagery on Thursday morning showed convective clouds over Jammu and Kashmir. Low to medium clouds (partly cloudy) were seen over Himachal Pradesh, Punjab, Uttarkhand and the Northeastern States.

Scattered to fairly widespread rain or snow is expected to occur over Jammu and Kashmir and Himachal Pradesh during the next 24 hours, and isolated thereafter. Scattered rain or snow will occur over Uttarkhand during this period. Scattered to fairly widespread rain or thundershowers have also been forecast for the Northeastern States. Isolated rain or thunderstorms are likely over Punjab, Haryana, Delhi and parts of west Uttar Pradesh during the next 24 hours.

Forecast for the week ending March 11 by the US National Centres for Environmental Prediction (NCEP) suggests that snow, rain and thunderstorms will prevail southward from Jammu and Kashmir, Himachal Pradesh, Uttarkhand, Punjab, Haryana, parts of north Rajasthan, Delhi and west Uttar Pradesh.

These (snow, rain, thunderstorms) will be piloted by back-to-back western disturbances trooping in from across the border around Saturday and by mid-week next week, according to predictions from the European Centre for Medium-Range Weather Forecasts (ECMWF).

Early forecasts by NCEP for the following week (March 12-20) suggest that western disturbances will continue to roll in, setting up the weather over north, extreme northwest, east and northeast India.

The weather will be particularly heavy over west Uttar Pradesh and along the Himalaya foothills and Nepal where heavy rains can trigger landslides, according to the forecasts.

New species of cuttlefish discovered

A new species of cuttlefish, which belongs to the genus of sepia vecchioni, has been discovered recently by the Fisheries College and Research Institute (FCRI).

It was spotted along the coastal area of Colachel in Kanyakumari district by FCRI scientists while carrying out an intensive research on cephalopod taxonomy. This species had been misconstrued as sepia prashadi so far, Dr. Venkataramani, Dean of the college, told The Hindu here on Tuesday.

With this species, the number of cuttlefish species recorded in the Indian seas has gone up to15. Referring to the etymology of the new species, Dr. Venkataramani said it was named after Dr. Michael Vecchione, a renowned cephalopod taxonomist. So it has been identified as patronymic species. “The sepia vecchioni has distinguished features of transverse zebra type white stripes facing upwards in the dorsal mantle of the body, four median suckers, three rows of biserial normal suckers and the arms are elongated whip like. They are fragile and elliptically oval shaped. It also shows a clear cut sexual dimorphism and in cuttlebone characteristics,” he said.

The scientists of FCRI would make an in-depth study on the biological status and stock assessment of the new species in the Gulf of Mannar, South East Coast of India, he added. During 2003, scientists found two new species of cuttlefish along Tuticorin coast and christened them sepia prabahari and sepia ramani.