As La Nina Tapers off, How will the Monsoons behave?

The IMD finally released their monsoon forecast, after dithering for some time.  Speaking to CNBC-TV18's Karan Thapar, Ajit Tyagi, Director General of the Indian Meteorological Department (IMD), said this year the forecast in quantitative terms is of 98%, which falls in the normal category. 

"We are confident within the model areas of plus/minus 5%. In extreme cases to be below normal category, which is between 90 and 96%—to be preciously the 93%, if we minus 5% from the 98%," he said raising hopes of higher farm output that could help the government tame high food prices."

As per the latest data from the Bureau of Meteorology, Australia, the La Niña, which brought above normal rainfall to India last year, has run its course with the central Pacific returning to El Niño-Southern Oscillation (ENSO)  neutral conditions as reflected by the Nino 3.4 Index being 0.4 C deg. Since January this year, due to the La Niña effect, daytime maxima have been too low for ‘monsoon comfort’ since sustained heating of the northwest region is crucial to set up the keenly watched ‘heat low’ to build. The heat low builds due to sustained heating of northwest India, adjoining Pakistan and the Arabia desert.  

It is these conditions what posed a dilemma for IMD in their forecast of the monsoon and they dithered finalizing it until it became clear that we have returned to ENSO neutral conditions by mid-April, which can reduce rainfall. in the country. We can now hope that daytime maxima returns to normal fully in May to establish the south-westerly monsoon wind regime before heavy monsoon rains start over western India. Unlike other low-pressure areas, the ‘heat low’ is topped up by clear, cloud-free skies due to special reasons associated with the geography.

Read More: http://devconsultancygroup.blogspot.com/2011/04/as-la-nina-tapers-off-how-will-indian.html

Unseasonably Heavy Rain Floods Thailand, due to last week's S-E Bay Low

Normally the end of March brings dry weather to tropical Thailand. In 2011, however, a powerful storm settled over the Malay Peninsula, bringing up to 1,270 millimeters (50 inches) of rain in little over a week. The intense rain flooded 8 provinces, killing 13 and affecting 842,324 people as of April 1, said the government of Thailand.
This image, made from the Multi-satellite Precipitation Analysis based on data from the Tropical Rainfall Measuring Mission (TRMM) satellite, shows rainfall for March 23–30, 2011. Rainfall totals range from 200 millimeters (8 inches) to more than 1,200 millimeters (47 inches) across the Malay Peninsula. TRMM measured the most rain immediately south of the city of Surat Thani.
According to AccuWeather, the region usually receives 1–3 inches (25–76 mm) of rain in March, though heavy downpours do occur at other times of the year. The unseasonal rain caused landslides and widespread flooding. One landslide, in the Krabi province on the mountainous west side of the peninsula, destroyed a village, leaving 100 people missing, reported the Thai newspaper, the Nation.

Australia :: Rain Transforms Channel Country

2-Mar-2011

8-Mar-2011

In early March 2011, over a period of just six days, the appearance of Australia’s Channel Country changed dramatically. Rainwater filled typically dry river channels throughout the region, particularly in southwestern Queensland.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured these images of southwestern Queensland and northeastern South Australia on March 2, 2011 (top), and March 8, 2011 (bottom). Both images use a combination of infrared and visible light to increase the contrast between water and land. Vegetation, even sparse vegetation, appears bright green. Clouds appear sky blue. Water varies in color from electric blue to navy. Bare ground appears pink-beige.
On March 2, water fills just a few channels and basins. Six days later, standing water is apparent throughout southwestern Queensland and northeastern South Australia. The largest expanses of water appear just north of the border between the two states.
Channel Country flooding is a fairly common occurrence at this time of year, but the summer of 2010–2011 proved to be one of Australia’s wettest on record, leading to extensive flooding. Agence France-Presse reported that Australia’s Bureau of Meteorology described average rainfall as 70 percent above normal. Topped only by precipitation received in 1973–1974, rainfall for 2010–2011 was the second-highest since recordkeeping began 111 years earlier. Meteorologists attributed the unusually heavy precipitation to La Niña weather patterns.

More heavy rain for E. Srilanka from 1-Feb to 7-Feb-2011

JAN-2011

FEB-2011

FEB-2011
A month after flooding killed 43 people and displaced over a million residents, torrential rains once again pummeled Sri Lanka. By February 6, 2011, rain had fallen for six consecutive days, forcing a quarter of a million people into government relief camps. Authorities confirmed eight deaths and listed two more people as missing, according to Deutsche Presse-Agentur.
This map shows rainfall amounts over Sri Lanka February 1 through 7, 2011. The heaviest rainfall—more than 600 millimeters (24 inches)—appears in dark blue. The lightest rainfall—less than 75 millimeters (3 inches)—appears in light green. Although the heaviest precipitation occurs offshore, significant rainfall extends over the entire island.
This image is based on data from the Multisatellite Precipitation Analysis produced at NASA’s Goddard Space Flight Center, which estimates rainfall by combining measurements from many satellites and calibrating them using rainfall measurements from the Tropical Rainfall Measuring Mission (TRMM) satellite.

‘El Nino-to-La Nina flip in 2010 rapidest ever'

Last year's transition from El Nino to La Nina was about the most sudden ever, according to Dr Tony Barnston, Chief Forecaster, International Research Institute (IRI) for Climate and Society at Columbia University.
Rapid flips like this in the past have ended up precipitating a two-year La Nina, such as right after the El Nino episodes of 1972-73 and 1997-98.
The likelihood of this happening with the current La Nina is unknown, Dr Barnston says.
The term La Nina refers to a period of cooler-than-average sea-surface temperatures in the eastern and central equatorial Pacific Ocean that occurs as part of natural climate variability.
La Nina has been found to correlate well with a reasonably good concurrent Indian monsoon, though without any direct cause-effect relationship.
This situation is roughly the opposite of what happens during El Nino events, when waters in above-mentioned Pacific region are warmer-than-normal.
A strong El Nino, as witnessed during 2009, has correspondingly been associated with dry or drought conditions in India, but with honourable exceptions as in 1997.

NEUTRAL CONDITIONS
Both are part of a larger climate cycle known as the El Nino-Southern Oscillation, or ENSO.
“Even if we do have a second year of La Nina developing in northern hemisphere summer 2011, we expect at least a brief return to neutral conditions from May to July of 2011,” he added.
Based on current observations and on predictions from models, the IRI sees at least a 90 per cent chance that La Nina conditions will continue through March 2011.
Because the Pacific is the largest ocean on the planet, any significant changes in average conditions there, such as those that occur during La Nina or El Nino, can have consequences for temperature, rainfall and vegetation in faraway places.

INTERESTING EPISODE
Once developed, La Nina conditions typically persist for 9-12 months, peaking sometime during November, December, or January.
But 2010 was an interesting and lively year for climate scientists, the IRI recalls.

For the first four months of this year, El Nino conditions prevailed in the tropical Pacific, but that quickly changed, and by June, a La Nina pattern had emerged.
Since 1950, the world experienced six major La Niña events, which were linked to widespread flooding in some areas.
What La Niña does is increase the likelihood that certain areas will get above-normal or below-normal rainfall. Hence, it can be associated with droughts as well.
It keeps east Africa drier-than-usual, sparking food-security concerns in areas lacking irrigation, including parts of Somalia, Kenya, Ethiopia and Tanzania.
Areas in southeastern South America, central southwest Asia, and the southern US may also see lower-than-normal rainfall for the first quarter of 2011.
But La Nina probably isn't to blame for the recent flooding in southeastern Brazil, says Dr Barnston.
The more likely culprit there was a pocket of above-average sea-surface temperatures in the southwest Atlantic that promoted low atmospheric pressure and an increased tendency for heavy rainfall, he says.

looks like a multiple year La Nina

Meteorological researchers and scientists around the world are now seized of the possibility of the ‘peaking' La Nina mutating into a multiple-year event.

The ‘super drencher' that evolved over the east-central Pacific during the last year and unleashed its fury over disparate continents may now be on the mend, according to top researchers.

AT ITS PEAK

But any ‘dramatic weakening' is ruled out, in any case, they aver. Dr Jing-Jia Luo, a leading Tokyo-based researcher informed Business Line that strong La Nina has reached its peak intensity and climb down intensity over the following months.

A Senior Scientist at the Climate Variation Predictability and Applicability Research Programme at the Research Institute for Global Change (RIGC), an affiliate of the Japan Agency for Marine-Earth Science and Technology (Jamstec), he, however, maintained that the Pacific event would still be ‘long-lasting' and persist until early 2012.

This is what makes it a multiple-year event, agrees Prof Bin Wang, Professor of Meteorology, Department of Meteorology and International Pacific Research Centre at the School of Ocean and Earth Science and Technology, University of Hawaii.

LIKELY CHANCE

“This looks like a multiple year La Nina. This seems very likely. Several previous strong La Nina events have tended to last longer than a year,” Prof Wang says.

Dr William Patzert, an oceanographer at the Jet Propulsion Laboratory of the US National Aeronautical and Space Administration, too, has taken exception to the La Nina event.

“In contrast with the more spectacular but shorter duration El Nino and La Niña events, this multiple-year trend may be part of a decade-long pattern known as the Pacific decadal oscillation,” Dr Patzert said. Closer home, India Meteorological Department (IMD) expected that there is a 50 per cent possibility of La Nina persisting around mid-year this year.

In its latest assessment, the Japanese RIGC said that associated with this strong La Nina event, global mean surface air temperature has decreased in last month and severe cold stormy weather unfolded in northern Eurasia and parts of North America. Surface air temperature in Eurasia, northern North America, Australia, Brazil, and Africa would continue to be below normal in following months.

More precipitation and flood events would occur in Australia, South Africa and Brazil during the first few months of 2011.

East China and Japan would have a hot summer in 2011 in association with the extended La Nina condition.

2010 was India's hottest year in recorded history

It now appears that the country may have endured the hottest year in 2010 in recorded history even as cold wave to severe cold wave conditions persist in north and north-west concurrently.

Mean annual temperature for the country as a whole during the last year was +0.93 deg Celsius above the 1961-1990 average.

WARMEST YEAR

It was slightly higher than that of the year 2009, making 2010 as the warmest year on record since 1901, an annual climate summary issued by India Meteorological Department (IMD) said on Friday.

Abnormally warm conditions (heat wave) prevailed over major parts of the country during March and April months claiming more than 300 lives.

The Pre-monsoon season was the warmest since 1901 with mean temperature being 1.8 deg Celsius above normal.

It is also found that the decade 2001-2010 has been the warmest decade with a temperature anomaly of 0.40 C.

LA NINA OUTLOOK

The annual total rainfall for the country as a whole was normal during 2010 with actual rainfall of 121.5 cm against the long period average (LPA) of 119.7 cm.

Monsoon season contributes about 75 per cent of total annual rainfall for the country as a whole. Seasonal rainfall during 2010 was 102 per cent of its LPA.

Significantly, the IMD says that probabilities for La Nina conditions are 94 per cent or more through the January-February-March, 2011.

These conditions, which are considered monsoon-friendly, are forecast to not drop to below 50 per cent until the April-June season, the IMD outlook said.

Analysing the report, sources in the Ministry of Earth Sciences said the hot summer and the eventful wet to wetter season were not confined to India alone.

SYSTEM LOCK-IN

While parts of Europe experienced flooding conditions during the period under reference, Russia underwent the fiercest drought in living memory.

A warming anomaly materialised over India as a semi-permanent ridge (high-pressure system with dry, sinking air in contrast to low-pressure systems with moist, rising air) locked into position across the northwest border.

This had effect of shutting out the calming influence of western disturbances, allowing the hot climes to anchor themselves over the region.

Lesser movement of western disturbances, however, worked to the advantage of the country with the monsoon circulation spared of having to run into the opposing flows associated with western disturbances.

According to sources, this is what helped bring rains in huge quantities over Rajasthan and Gujarat during the monsoon.

Death toll due to heavy rains/floods during the monsoon was more than 500, mostly from northern and northwestern parts, the IMD report said.

A cloud burst in early hours of August 6 in Leh claimed more than 150 lives and more than 500 people are missing.

It is now a given that the atmosphere has warmed up to unprecedented levels, the sources explained. A warmed up atmosphere has the capacity to hold correspondingly larger amount of moisture.

Since the atmosphere cannot hold the moisture for too long, it cannot but precipitate. The air masses transport the moisture from areas of higher pressure to those of lower pressure.

Depending on locally evolving favourable conditions, clouds build up and the moisture gets precipitated.

The spatial distribution is not equal at any given point of time, with seasonal ‘hot spots' receiving the largest precipitation.

The monsoon region offers itself up as a ‘hot spot' and the weather gets amplified over disparate locations depending on extra moisture load in the air mass.

These phenomena are revealed in their gigantic size and scale in the deep ocean basins of the Pacific and the Atlantic where tropical storms and cyclones sustain themselves for up to a week.

Not to the same extent in the rather ‘closed basins' of the Arabian Sea or the Bay of Bengal where these systems can live up to three or four days at the most.

La Nina to stay course, assert Japanese researchers

Japanese researchers have maintained the outlook for the prevailing La Nina to peak over the next few months and last into early 2012 even as peer models from around the globe are less assertive.

The monsoon-friendly event might be long-lasting and persist till early 2012, the latest update from the Tokyo-based Regional Institute for Global Change (RIGC), an affiliate of the Japan Agency for Marine-Earth Science and Technology, said.

The Climate Prediction Centre of the US National Weather Services and the Australian Bureau for Meteorology have stopped short of taking a call beyond the northern hemisphere spring for La Nina to continue.

Associated with this strong La Nina event, surface air temperature over many parts of the globe is expected to look down during the 2010-11 winter.

But South-East North America may experience warmer-than-normal winter. Parts of North-East Asia (including Japan) also might have warmer-than-normal winter.

Above-normal precipitation is likely over Australia, South Africa, North-East Brazil and South Asian countries, the RIGC said in its outlook.

WARM ANOMALY

December, January and February could witness cooler-than-normal climes in India except West Rajasthan, Jammu and Kashmir, Punjab, Haryana, Jammu and Kashmir and the northeastern States where temperatures could rise to slightly above normal.

The warmth is attributed to a cascading impact from across the border, with West Asia, Pakistan and Afghanistan expected to witness warmer than normal winter.

The RIGC also supported the outlook for possibility of above-normal summer showers for southern peninsula early next year. A similar trend could be evident to a lesser extent over parts of East and West India.

Meanwhile, an India Meteorological Department (IMD) weather update for the 24 hours ending Tuesday morning said mainly dry weather prevailed over the country except scattered rain over Tamil Nadu.

The causative upper air cyclonic circulation persisted over South Tamil Nadu and neighbourhood.

Dry but cool northwesterly winds are prevailing over North-West and Central India. Cloud-free skies have caused minimum temperatures to fall by 2 to 3 degree Celsius over many parts of Central and East India.

Actual minimum temperatures recorded ranged between 4 to 8 degree Celsius over many parts of North-West and Central India.

The lowest recorded minimum temperature in the plains of North-West India during this period was 3 degree Celsius at Narnaul (Haryana).

Forecast valid until Saturday spoke about the possibility of scattered rain or thundershowers over extreme South Peninsular India.

A feeble western disturbance is expected to cause light precipitation over Jammu and Kashmir from Wednesday onwards.

Mainly dry weather would prevail over plains of North-West, West, Central and East India.

The European Centre for Medium-Range Weather Forecasts saw the possibility of accentuation of a trough from the seas to the south of Sri Lanka from Saturday onwards.

It is shown as propagating itself a little to the north to impact Sri Lanka and extreme South Indian peninsula.

Scattered rains are indicated for Coastal Tamil Nadu as well as for the South-West Coast (Kerala and Karnataka) during the week ending December 22, according to the US National Centres for Environmental Prediction.

Breaking News: Cyclone Giri strikes Western Myanmar, Typhoon Megi ravages Taiwan on the way to China

Just minutes ago, comes the news that Cyclone Giri made a landfall in Mynamar threatening to unleash flooding and landslides. The satellite photo shows Giri making a landfall, near Kyaukphyu, a large island in western Myanmar.  

Read more: http://devconsultancygroup.blogspot.com/2010/10/breaking-news-cyclone-giri-strikes.html

Early winter: The signals of a La Nina Winter ???

UK is to be hit by an arctic blast, early this week, with minimum temperatures set to plunge -6C. Maximum temperatures meanwhile are likely to plummet to 7C. This is half the average for the time of year, but will feel more like 3C due to the effect of biting winds. Met Office forecaster Robin Downton was quoted by the Sun as saying, “It's fairly early on to be getting temperatures below freezing." 

In India, by second week of September, the higher reaches of Garhwali Himalayas received snowfall, sending the mercury plummeting in Chamoli and Rudraprayag districts. The hills around Badrinath and Kedarnath temples also have received snowfall while lower areas received rainfall forcing the people to take out their woollens. The higher hills in Lahaul and Spiti, Chamba, Kinnaur and Kullu districts also experienced mild snowfall. Rohtang Pass, located at an altitude of 13,050 feet was clad in two to three inches of snow by mid- last month.

Read More: http://devconsultancygroup.blogspot.com/2010/10/early-winter-signals-of-la-nina-winter.html

Now, the Monster of a La Nina Confirmation??

In the context of recent plunge of the MEI into strong La Nina conditions, what does a comparison figure with strong La Nina events that all reached at least minus one standard deviations by June-July, and a peak of at least -1.4 sigma over the course of an event show?

A monster La Nina underway!

Read more: http://devconsultancygroup.blogspot.com/

La Nina in progress

Continuing a trend that began earlier in the year, La Niña conditions strengthened through the summer of 2010, evidenced by a streak of cool water across the equatorial Pacific Ocean.
Acquired by the Ocean Surface Topography Mission/Jason-2 satellite, this map shows a 10-day average of sea-surface height centered on September 6, 2010. Because water expands with rising temperatures, satellites can use sea-surface height as a proxy for temperature. Areas where the water surface is higher (and therefore warmer) than average are shades of red-brown, and areas where the water surface is lower (cooler) than average are blue. Normal conditions appear in white.
The El Niño weakens the westward trade winds that normally blow over the eastern tropical Pacific Ocean. Those winds keep eastern Pacific waters cool and concentrate warm waters in the western Pacific. A weakening of trade winds enables warm waters to gradually spread eastward, heating up the central Pacific. La Niña typically follows El Niño, and causes essentially the opposite conditions. La Niña strengthens the trade winds, spreading cool water from the South American coast to the central Pacific. This see-saw pattern of El Niño and La Niña can drive large-scale weather changes, especially in the tropics.
This map reveals a broad swath of cool water stretching from South America to New Guinea. The ocean is not, however, uniformly cool. Pockets of warm water are mixed with the cool, particularly in the western Pacific. Warmer waters in this region can lead to increased rainfall, and La Niña conditions may have played a role in the devastating floods in Pakistan during the Northern Hemisphere summer of 2010.
Over the eastern Pacific Ocean, cooler waters lead to less moisture along the coasts of North and South America. So as more rain pounds some parts of the globe, La Niña conditions can deepen drought in others. By the time La Niña conditions intensified in September 2010, the southwestern United States had experienced more than 10 years of mostly dry conditions. A release from NASA’s Jet Propulsion Laboratory reported that the American Southwest might experience not only drier conditions, but also intensified wildfires under strong La Niña conditions.
OSTM/Jason-2 is a joint oceanographic mission of NASA and the Centre National d’Études Spatiales (CNES), France’s space agency.

How silly can Greenpeace get? Imagine appealing to Dr. ManMohan Singh to save our Monsoons!!

The year 2009-10, India suffered its worst drought in almost four decades, with monsoon rains 22% below average. As seen in the the photo, Greenpeace activists hung an 80-foot banner from the Mumbai-Thane Bridge addressed to the Indian prime minister on June 4, 2009.It requested him to save our monsoons given the drought situation. How mischievous this tactic is illustrated by their article 29th June 2009, titled “It’s anomaly reigning” posted 29th June 2009 in their website - just a few days after this stunt:

“On assessing the historical data, the Intergovernmental Panel on Climate Change in its fourth Assessment Report suggested, “warming in India is likely to be above the average for South Asia, with an increase in summer precipitation and an increase in the frequency of intense precipitation in some parts.” That the Indian monsoons are going to undergo gross changes as a direct result of climate change – rainfall will increase by ~ 20 per cent overall in the summer monsoon, but the distribution of this increase will not be evenly spread across the country.”

So what's Greenpeace's actual position any way? Does global warming cause increased or decreased rainfall? But it does not matter really as global warming or CO2 has nothing to do with monsoon intensity. But it finds a strong correlation with ENSO

Read more: http://devconsultancygroup.blogspot.com/2010/09/how-silly-can-greenpeace-climate.html

Leh Cloudburst: What caused it? The Most Plausible Theory

There are many presumptive theories floating around on what triggered the Leh Cloudburst. Some are on the lines of conspiracy theories like those attributing it to Chinese  targeting the country with their weapon modification program. Others sound seemingly outright outlandish being attributed to UFO activities. Still there are others blatantly anti-Green, accusing massive reforestation and afforestation drives over the decades as being responsible for the disaster. 

Some simply end up stirring a controversy, like those blaming the disaster on on global warming. The remaining theories suggest the disaster was caused by natural climatic phenomena. However, these still fall short of offering a complete synoptic explanation of what forces actually caused the strong updraft and downdraft that led to the cloudburst in the first place.

If we need to crack the Leh Cloudburst in order to adequately and scientifically explain it, then we must identify what forces were behind both the strong updraft and downdraft. We examined seven major theories in attempt to understand which among them appeared most plausible.

Read more:
http://devconsultancygroup.blogspot.com/2010/08/leh-cloudburst-what-caused-it-most.html