Northeast monsoon below normal, triggers drought fear across south India
The statement went on to note that seasonal rainfall over the southern peninsula, which includes five meteorological subdivisions (coastal Andhra, Rayalaseema, Tamil Nadu and Puducherry, south interior Karnataka and Kerala), had also received below-average rainfall in the same months.
In Andhra Pradesh, Visakhapatnam, Guntur and Prakasam districts received 54%, 63% and 68% less rainfall.
The southwest monsoon, the country’s principal monsoon season, also ended on a ‘below normal’ note, triggering droughts in several states.
“It is likely that several states are heading into severe drought, and the water crisis is expected to worsen in the coming months as the summer sets in.
The ‘other’ monsoon South Asia has two monsoons: the southwest or summer monsoon from June to September, and the northeast or winter monsoon between October and December.
According to a 2012 study, India receives about 11% of its annual rainfall – with many districts in the south receiving 30-60% – during the northeast monsoon season.
A 2017 report prepared by the Regional Meteorological Centre, Chennai, reads: … for the extreme southeastern state of Tamil Nadu and the Union Territory of Puducherry…, the normal southwest monsoon seasonal rainfall realised is only about 35% (317.2 mm) of its annual rainfall (914.4 mm) as this subdivision comes under the rain-shadow region during the southwest monsoon.
On September 29 last year, the IMD issued an operational forecast for the 2018 northeast monsoon, saying that the rainfall over the south “is most likely to be normal (89%-110% of long period average), with a tendency to be [on] the positive side of the normal.” It added that the rainfall over Tamil Nadu is most likely to be above normal, i.e. over 112% of the long-term average.
And “apart from the global weather phenomenon of the El Niño Southern Oscillation, the northeast monsoon is also affected by factors like the Indian Ocean dipole and the Madden-Julian Oscillation,” he said.
Oscillations are climate patterns that involve a back-and-forth variation of some climate variable.
Southwest drought status is mostly nonexistent
As Southwest summer’s typically go, this one doesn’t seem to be starting off too typically, at least not compared to many of the recent early summer weather patterns.
Texas shows 1 percent of the state rated in drought, with five small areas scattered in Northeast and Central Texas showing only moderate drought.
The drought monitor rates a few areas across the state as abnormally dry, but the vast expanse of Texas remains white—drought free—on the drought monitor map.
Oklahoma is rated drought free in the latest drought monitor map available, with only a few small spots in the Southwest corner, South Central and the Southeast corner considered abnormally dry.
Three counties in southwest New Mexico are considered in moderate drought.
A small sliver of one county on the Texas State line in Southeast New Mexico is the only other spot considered abnormally dry.
Overall, the map shows only 6.5 percent of the state in moderate drought status.
New Mexico showed 36 percent rated in drought status at this time last year.
The Climate Prediction Center expects the El Niño Southern Oscillation to remain neutral through the rest of the year.
Summer rainfall in vulnerable African region can be predicted
Summer rainfall in vulnerable African region can be predicted.
Summer rainfall in one of the world’s most drought-prone regions can now be predicted months or years in advance, climate scientists at the Met Office and the University of Exeter say.
The Sahel region of Africa — a strip across the southern edge of the Sahara from the Atlantic Ocean to the Red Sea — is a semi-arid landscape between the desert to the north and the savannah to the south.
The new research used the Met Office Hadley Centre’s Decadal Prediction System and found that the model was good at predicting summer Sahel rainfall over the forthcoming five years.
Forecasting years ahead relies on sea surface temperature in the North Atlantic, whereas the El Niño Southern Oscillation is important for a shorter-term forecast before each summer.
"Our study suggests that skilful predictions of summer rainfall in the Sahel are now possible months or even years ahead," said Dr Katy Sheen, formerly of the Met Office but now of the University of Exeter’s Penryn Campus in Cornwall.
"With a population reliant on agriculture, the Sahel is particularly vulnerable to major droughts, such as those of the 1970s and 1980s.
"Improved understanding and predictions of summer rainfall in the Sahel has the potential to help decision makers better anticipate future cycles of summer droughts and floods, helping local communities become increasingly resilient to the region’s notoriously variable and changing climate."
"Our study improves our understanding of the driving mechanisms of summer rainfall variability and shows they are predictable," Dr Sheen added.
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Dramatic cholera outbreaks in East Africa linked to extreme El Niño event
Dramatic cholera outbreaks in East Africa linked to extreme El Niño event.
Scientists have established a link between El Niño and cholera epidemics in Africa.
A study conducted in Bangladesh revealed an association between the El Niño-Southern Oscillation (ENSO) cycle and cholera.
El Niño is a climate cycle which has a global impact on weather patterns including tropical storms and drought.
The new research published in the Proceedings of the National Academy of Science is the first to tackle this issue.
They created high-resolution maps of cholera incidence and discussed the factors that could explain the outbreaks – whether population density, access to drinking water, access to sanitation, and distance to nearest major water body.
The scientists found that while the total number of cholera cases did not vary between El Niño years and non-El Niño years, the geographic distribution of cases did.
There were approximately 50,000 additional cases in East Africa during and following El Niño years and 30,000 fewer cases in southern Africa.
Thus, increased rainfall in East Africa partly explained why the number of cases exploded during El Niño.
We saw an association between rainfall and disease, at least in the few regions of East Africa where we know that rainfall tends to be higher during El Niño years", Moore pointed out.