Bharat Rakshak

According to Singh et al., spacecraft data have been revolutionary for weather prediction in the Southern Hemisphere, where ground measurements are sparse. However, as the suite of orbiting instruments grows, it is unclear if all these new observations result in better predictions. The authors decided to test the impact of a broad array of observing systems on weather forecasting models over India. The team carried out 21 experiments through July–the summer monsoon season—in 2012.

Their analysis shows that wind observations have a large impact on the accuracy of a forecast, especially in the short term. Removing wind observations reduced the accuracy of a forecast’s rainfall estimates by as much as 30%. Unfortunately, current space-based weather instruments are heavily biased in favor of measuring atmospheric mass instead of wind, the authors say. That will change, the authors say, when the European Space Agency’s Atmospheric Dynamics Mission (ADM-Aeolus)—the first spacecraft to acquire global wind profiles—launches in 2015.

The instrument that played the largest role in reducing forecasting errors, including rainfall predictions, is one that weather agencies have used regularly for close to a century: radiosondes. The expendable instrument packages, mounted to small weather balloons, relay pressure profiles, temperature, and relative humidity. The instruments also measure wind speed and direction. (Journal of Geophysical Research: Atmospheres, doi:10.1002/2014JD021890, 2014)

—Eric Betz, Freelance Writer

G.S. Mudur

New Delhi, April 26: The earthquake that convulsed Nepal yesterday triggered dozens of aftershocks and a fresh quake today, implying what some scientists said is an eastward-moving subterranean instability whose pattern and outcome cannot be predicted.

Indian government seismologists documented more than 45 aftershocks today after yesterday's 7.9-magnitude earthquake, as well as a 6.9-magnitude earthquake 65km east of Kathmandu a little past noon. Yesterday's earthquake had its epicentre about 77km northwest of Kathmandu.

"Most (of the) aftershocks had magnitudes between 4 and 6," said Laxman Singh Rathore, director-general of the India Meteorological Department.

"They may continue for some time, with smaller magnitudes. We cannot predict how long they may last --- weeks, months or even years."

Since the primary earthquake, a 6.6-magnitude aftershock yesterday and the 6.9 earthquake today shook buildings and structures across several states in northern and eastern India.

Today's tremors from the 6.9 earthquake, which Calcutta felt eight seconds past 12.38pm, were over in 10 seconds; yesterday's shake from the primary quake had lasted a minute and a half.

Preliminary observations of the focal mechanism of yesterday's primary earthquake suggest that it occurred in what some scientists consider a "dangerous zone".

Its epicentre, about 15km under the ground, lies within what geologists call the Main Himalayan Thrust, the wedge-shaped section of the Indian plate that has slipped beneath the Tibetan plate as the Indian continental plate thrusts under the Eurasian plate at about 45mm per year.

"A primary event on the Main Himalayan Thrust is something that worries me," Sridevi Jade, a senior scientist at the Council of Scientific and Industrial Research Centre for Fourth Paradigm Institute who has conducted extensive research in the Himalaya, told The Telegraph .

Today's earthquake, Jade said, suggests an eastward-moving instability.

Geophysicists are concerned that the primary earthquake, which released energy equivalent to 712 Hiroshima-class atomic bombs, may have transferred some of its energy elsewhere and destabilised the Main Himalayan Thrust, giving rise to the earthquake east of Kathmandu today.

"The 6.9 quake today is certainly not an aftershock," said Shyam Sunder Rai, professor of earth sciences at the Indian Institute of Science Education and Research, Pune.

"Yesterday's main event and today's quake occurred in two completely different domains."

For earthquakes to be labelled "aftershocks", Rai said, they need to occur in the close vicinity of the primary epicentre and be linked to the same geological fault system.

But a US-based geologist cautioned that it might still be too early to say whether today's earthquake was an aftershock or a new event.

"The strict definition is that an aftershock should occur within the fault area that ruptured in the original earthquake," said Larry Ruff, a seismologist at the University of Michigan who has studied large earthquakes around the world.

"But we need to know the exact limits of the section of the original fault that broke --- and we don't know that for the Saturday earthquake yet."

Ruff is now trying to get the best estimate for the length of the rupture using seismic waves data.

According to Ruff, energy propagation after an earthquake is a phenomenon even mechanical engineers studying cracks in materials are familiar with. Stresses can build at the edge of the crack and such energy transfer may load tectonic strain at other sites along a fault.

The North Anatolian fault in Turkey is an example where an earthquake in the mid-20th century propagated energy elsewhere along the fault.

As the plates push against each other, friction generates stress and energy that builds until the crust ruptures, said Dr. Chan, who compared the quake to a thermonuclear weapons explosion. In the case of Saturday’s quake, the plate jumped forward about 2 meters, or 6.5 feet, said Hongfeng Yang, an earthquake expert at the Chinese University of Hong Kong.
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The most visible result of this is the Himalayan mountain range. The fault runs along the 1,400-mile range, and the constant collision of the India and Eurasia plates pushes up the height of the peaks by about a centimeter each year.

Despite the seeming regularity of severe earthquakes in Nepal, it isn’t possible to predict when one will happen. Historic records and modern measurements of tectonic plate movement show that if the pressure builds in the region in a way that is “generally consistent and homogenous,” the region should expect a severe earthquake every four to five decades, Dr. Yang said.

The complexity of the forces applying pressure at the fault means scientists are incapable of predicting more than an average number of earthquakes that a region will experience in a century, experts say.

Still, earthquakes in Nepal are more predictable than most, because of the regular movement of the plates. Scientists aren’t sure why this is.

The thundershowers were so widely spread that only one (Odisha) of the 36 meteorological subdivisions finds itself in the rain-deficit category. Elsewhere, the rain has been excess or normal.

Soil moisture

A leading US-based private weather forecaster has said that the rainfall excess should hold the drought-prone west and north-west India and parts of peninsula in good stead. The moisture conserved would help with the sowing process ahead of the South-West monsoon, which India Met Department has forecast to be below normal this time round.

Favourable moisture for much of the country should aid grain/oilseed development, according to this forecaster.

Main forecast drivers are the warming trend of the Indian Ocean (Indian Ocean Dipole status) and weak to moderate El Nino in east and equatorial Pacific. A third of the area for cotton, sugarcane and groundnuts towards the south of the country may be faced with dryness concerns, the agency suspected.

If an earthquake were to hit India right now, let alone early warnings, scientists may even struggle to evaluate its scale and characteristics and also predict aftershocks.

The country’s network of “ground-motion” detectors, the backbone of quake monitoring, has not been working for nearly eight months now due to a bureaucratic bottleneck, putting millions of lives at risk.

As the Nepal quake rippled across most of India, top geologists logged in to a designated website for data to analyse the event. When they failed to find any data on the 7.9-magintude quake that set off in Lamjung, Nepal, they found that strong-motion detectors were lying idle.

Ground or strong-motion detectors -- also called accelerographs -- are critical as they serve as the basis for India’s earthquake early-warning system.

In absence of vital information, scientists would find it difficult to evaluate a quake properly. “You could say earthquake sciences begin with them,” one expert told HT, requesting anonymity because he receives state funding for his research.

India’s network of 300 strong-motion sensors, installed at critical points across 14 states, cover high-risk seismic zones V and IV as well as some heavily populated cities in zone III. These include Himachal Pradesh, Punjab, Haryana, Uttarakhand, Uttar Pradesh, Bihar, Rajasthan, Sikkim, West Bengal, Meghalaya, Assam and Andaman and Nicobar Islands.

These imported devices, which measure movement generated during a quake and also help identify areas that could be vulnerable, cost Rs 10 crore to install and about Rs 1 crore a year to maintain.

“Ground-motion data is also vital to determine quake characteristics at different places and designing over-ground structures, such as buildings. For instance, during a quake, Kanpur will shake differently from Delhi,” said Dr CP Rajendran, a seismologist with the Bangalore-based Jawaharlal Nehru Centre for Advanced Scientific Research.

The network is now idling, following a decision to shift its command centre from the Indian Institute of Technology, Roorkee to the newly set up National Centre for Seismology, which isn’t fully functional yet.

The government moved the project out of IIT-R after it decided to carve out a separate seismological organisation from the India meteorological department. Funding was cut off in September 2014, without an alternative arrangement in place.

The decision was natural because after successful trials, these instruments had to be moved to be permanently maintained, a senior government official said.

“After successful experiments, these instruments have to be permanently made operational. Data is still available. If at all, this is a temporary gap,” Shailesh Naik, the earth sciences secretary, told HT.

On the ground, the changeover hasn’t been smooth. “These accelerographs have to be always on a ready-to-record mode. They have to be inspected frequently. That is not happening because we have no funds. The government hasn’t event taken custody of its keys from us,” Prof Ashok Kumar, who oversaw the project at IIT-R, said.

Networks of accelerographs are operative in several quake-prone regions of the world, offering continuous direct recording linked to computers and the internet.

Some of the problems in India represent classic red-tape. The IMD isn’t happy, a source said, to see a critical wing -- seismology -– being taken away. All this has meant a rough transition, resulting in stalling of a critical quake monitoring system.

However, by far the greatest risk from earthquakes in South Asia is currently not from its nuclear facilities but from its fragile dwellings that will collapse in quite modest future shaking. Deaths from future earthquakes could be vastly reduced, with no additional scientific input, were governments to enforce existing construction codes. Conversely, the development of improved estimates of seismic risk will be futile if governments permit unauthorized and unsound construction practices to continue (3, 4).

The monsoon current has set up nicely just south of Srilanka already this year. The winds are sweeping from the Pacific into the Indian ocean before their characteristic hairpin turn off East Africa. All it now needs is strong heating on North India to pull it up North. Hopefully no disruptive low pressure sets up. Fingers crossed.

Yes! needs to get warmer. Upper 40's in the Northern plains is optimal. Lower 40's is not enough. Without the heating of the Northern plains Bengaluru would be more like Somalia.....

Theo_Fidel wrote:Yes! needs to get warmer. Upper 40's in the Northern plains is optimal. Lower 40's is not enough. Without the heating of the Northern plains Bengaluru would be more like Somalia.....

chaanakya wrote:Northern plains fare no better. and is needed to set up low pressure zone for monsoon to rush in. Bangalore , situated at higher elevation of 920 Mts compare to Delhi at 273 Mts would witness temperature lapse of about 5 to 6 deg Celsius. So it should be cooler generally but with early arrival of monsoon drop should be more rapid. Even occasional showers would send temp tumbling down.

Indian Ocean hides Global Warming
20/05/2015
A team of scientists from the US and the German GEOMAR Helmholtz Centre for Ocean Research Kiel was able to now show that the heat content of the Indian Ocean has risen substantially since late 1990s although the global temperature showed only little changes. This increase is very likely caused by a higher heat transfer from the Pacific to the Indian Ocean, as the authors report in the international scientific journal Nature Geoscience.

20150519 Indian Ocean Heat Transport model - Image courtesy by GEOMAR

Although the emissions of greenhouse gases continued to rise steadily, global warming seems to pause unexpectedly at the end of the 20th and the beginning of the 21st century. In a recent study that used observational data as well as model results researchers were able to show that the Indian Ocean has stored much more heat in the past two decades than in previous times. A large fraction of the heat has been transferred from the Tropical Pacific via the Indo-Pacific Archipelago into this part of the world ocean.

Initially the hypothesis was that above average heat was stored in the Pacific, according to Dr. Wonsun Park, co-author from GEOMAR Helmholtz Centre for Ocean Research Kiel. The researchers had to reject this hypothesis because observed hydrographic data showed a decline of the heat content in the Pacific. Thus, lead author Dr. Sang-Ki Lee from University of Miami and NOAA AOML conducted a series of comprehensive model studies. With these results Sang-Ki Lee and Wonsun Park were able to come up with a conclusive mechanism to explain the pause of global warming.

In the Indo-Pacific region the past two decades were characterized by enhanced “La Niña-like” conditions with cold waters in the Eastern Pacific and warm waters in the Western Pacific. Driven by the enhanced trade wind system, warm water was moved westward by the Indonesian throughflow into the Indian Ocean. Finally, about 70% of the global heat uptake is stored in the upper 700 metres of the Indian Ocean.


The results of this study underpin the importance of the Indonesian throughflow as an important part of the global (thermohaline) circulation, according to Mrs Sang-Ki Lee. The accumulated heat could be redistributed globally by other ocean currents such as the Agulhas current and finally may reach the Atlantic. At present stage, it is unknown which climate variations might be affected due to this redistribution of heat. This phenomenon will be observed and the researchers are to conduct further model studies.


Original publication: Lee, S.-K., W. Park, M. O. Baringer, A. L. Gordon, B. Huber and Y. Liu, 2015: Pacific origin of the abrupt increase in Indian Ocean heat content during the warming hiatus. Nature Geoscience, doi:10.1038/ngeo2438.



Image: Schematic diagram of sea surface height changes and the Indonesian throughflow in the past 20 years. Background: sea surface temperature. Image courtesy: NOAA.

Nature: A new study suggests that the Indian Ocean may be storing 70% of the heat absorbed by upper oceans globally over the past decade. If so, that could be a major reason why global warming has appeared to slow in the same period. Observers had thought that the slowdown was due to oceans absorbing heat from the atmosphere, but measurements of upper ocean temperatures showed them to be lower than expected in the Pacific Ocean and higher than expected in the Indian Ocean. Now Sang-Ki Lee of the University of Miami, Florida, and his colleagues have created a model that explains how heat could have flowed from the Pacific to the Indian Ocean through Indonesia. However, the model only looks at the upper 700 m, so it doesn't account for heat sinking to deeper levels. Also, some separate temperature estimates based on satellite data don't match the NOAA data that Lee's team used for their model.

sanjaykumar wrote:http://www.theguardian.com/news/2015/ma ... -by-carbon

.....rapid development will require India to double or triple its production of coal – and make it the world’s second largest carbon emitter.

Meanwhile, the government has just introduced new pollution standards for coal plant technology – as strict as any in the world. “You will no longer be able to burn coal cheaply and pollute,” said Bushan. Under these rules, old plants such as Shaktinagar and Anpara A will have to be scrapped.

Bushan warned that better regulations would not necessarily be enforced. “The arm of the law is not always long in India. But there are certain trends that are positive. I am impressed quite frankly with the Modi government on these issues. They’ve done more than I expected.”

Scientists at the India Meteorological Department warn that not only has India turned hotter in the last two decades, but that heat waves are projected to become more intense, have longer durations and greater frequency, thereby resulting in more deaths

This result directly challenges what the UN's Intergovernmental Panel on Climate Change (IPCC) concluded in 2013, when it reported that global temperatures rose at a far lower rate between 1998 and 2012 than from 1951 to 2012 (0.05°C per decade compared to 0.12°C per decade). According to the authors of today's study, however, the IPCC's data was flawed. Using corrected measurements and more recent data, they find that temperatures rose at a rate of 0.106°C per decade between 1998 and 2014, more than twice the rate they reported with older data and without adjusting for biases. That's also on par with the 0.113°C rate they report for 1950 to 1999.

Arsenic was first detected in Kolkata in 1993 by Chakraborty. At present, almost 80 wards out of the 144 wards in Kolkata are in the grip of arsenic. While the permissible limit suggested by WHO is just 10 micrograms per litre, water samples collected from some areas in South Kolkata, such as Jadavpur and Bikramgarh, contained much, much higher doses of arsenic. Some samples contained even 199 micrograms per litre.

“But now that Chinese scientists claim that even this level could shoot up by a few hundred times — at least temporarily — just after the tremors, it could trigger a hundred questions. But it’s possible,” Chakraborty said.

Theo_Fidel wrote:It has been an excellent monsoon so far. Something like 40% above average. As usual IMD got the entire forecast catastrophically wrong.