Monsoon 2016 Archives - The India Climate Observatory

Monsoon weekly report card 2016

August 18, 2016 by Climate portal editor Leave a Comment

Employing the modified rainfall measurement categories, we have prepared a ‘report card’ for ten weeks of rainfall beginning with the week 02-08 June and continuing until the most recent which is the week of 04-10 August. This ‘report card’ is based on the recorded rainfall for each district and how much it varies from the normal for that particular week. This variation is portrayed by our ‘report card’ through the modified categories, which are designed to show more finely not merely deficient or excess rainfall, as the current categories do, but the degree of deficiencies or excesses for that district, for that week.

Our indicator of eleven grades (compared with the four of the India Meteorological Department, IMD) uses the same weekly district data to provide greater detail about rainfall adequacy or lack. Using this method we can immediately see from the chart:

1. From the week ending 22 June there have been a large number of districts – between 20% and 40% of all districts for which data is available – included in the four categories that describe rainfall of +20% above the normal.

2. That notwithstanding the overall seasonal prediction of monsoon 2016 having thus far been proved correct, there are almost every week a sizeable number of districts falling in the three categories for deficient rainfall.

3. That for the ten weeks in our report card the number of districts in the -21% to -40% below normal band is greater than the number of districts in the band for +21% to +40%.

In the chart, each bar corresponds to a week of district rainfall readings, and that week of readings is split into eleven grades (plus one for no data). In this way, the tendency for administrations, citizens, the media and all those who must manage natural resources (particularly our farmers), to think in terms of an overall ‘deficit’ or an overall ‘surplus’ is halted.

We find that our modified rainfall categories are more informative at the district level – and therefore cumulatively at the state and meteorological sub-division levels too – and can readily be adopted by administrations and planners.

In today’s concerns that have to do with the impacts of climate change, with the increasing variability of the monsoon season, and especially with the production of food crops, the IMD’s stock measurement – ‘normal’ is rainfall up to +19% above a given period’s average and also down to -19% from that same average, ‘excess’ is +20% rain and more, ‘deficient’ is -20% to -59% and ‘scanty’ is -60% to -99% – is no longer viable.

Heavy rain alert for Bihar, Uttar Pradesh

July 19, 2016 by Climate portal editor Leave a Comment

Heavy and very heavy rainfall is expected today 19 July and until 22 July in Bihar, eastern Uttar Pradesh and sub-Himalayan West Bengal. The India Meteorological Department has issued a heavy rainfall alert for these regions.

These are the districts which will be the most affected:
In Bihar – Paschim Champaran, Gopalganj, Purbi Champaran, Siwan, Chhapra, Muzaffarpur, Sitamarhi, Madhubani, Darbhanga, Supaul, Saharsa, Madhepura, Purnia, Katihar, Kishanganj, Araria.
In Uttar Pradesh – Pilibhit, Shahjahanpur, Kheri, Hardoi, Sitapur, Shrawasti, Bahraich, Gonda, Balrampur, Basti, Sidharthnagar, Sant Kabir Nagar, Gorakhpur, Deoria, Maharajganj, Kushinagar.

These are the five river sub-basins of the Ganga basin which are affected:
Gomti – including the Kathna, Sarayan, Kalyani rivers. Cities in this sub-basin – Sitapur, Hardoi, Lucknow, Rae Bareli, Sultanpur, Jaunpur.
Ghaghara – including the Saryu, Rapti, Chhoti Gandak rivers. Cities in this sub-basin – Lakhimpur, Shrawasti, Gonda, Faizabad, Basti, Gorakhpur, Kushinagar, Deoria, Siwan, Ballia.
Ghaghara confluence to Gomti confluence – including Chhoti Saryu and Mangal rivers. Cities in this sub-basin – Faizabad, Nizamabad, Azamgarh, Mau, Ghazipur, Buxar, Bhojpur, Chandauli.
Kosi – including Kamala, Pipra, Dhemra rivers. Cities in this sub-basin – Sheohar, Sitamarhi, Darbhanga, Supaul, Madhepura, Saharsa, Kishanganj, Khagaria.
Bhagirathi – including Fariyani Nadi and Kamla rivers. Cities in this sub-basin – Araria, Purnia, Sahibganj, Malda (West Bengal).

In the Middle Ganga plains, the water drainage lines govern the human occupancy of land, particularly the agricultural land and settlements. The rivers meet at acute angles and several tributaries form parallel or sub-parallel lines to the main stream. The major rivers that meet the main stream in the middle plain are the Gandak, the Kosi, the Sone and other small tributaries of Ganga like the Tons, the Karmansa, the Chatar, the Jargo, the Karnauti, the Khejuri on the west of the Sone and those on the east of the Sone are the Punpun, the Mohini and the Chandan.

Floods are recurring feature in this region particularly in the North Ganga plains. Almost all rivers in this middle plain develop a capacity to spill over in the monsoon period and are notoriously dynamic in character, particularly the Rapti, the Ghaghara, the Gandak, the Kosi, the Sone and the main Ganga itself.

Rivers before states

June 29, 2016 by Climate portal editor Leave a Comment

Our view of where water falls during the monsoon and where it is used has tended to follow the administrative unit view. That is, which state has experienced normal, above normal or deficient rainfall or which meteorological division has experienced normal, above normal or deficient rainfall.

Such a view has obscured an important ground reality, and this is that when it rains, surface water follows the contours and topography of watersheds and third-level basins, themselves subsets of sub-basins and then river basins. Thus when rain falls, water collects and begins to flow, it is natural to look for where it flows and where it may be collected instead of whether it is measured on one side or another of an imaginary boundary, which is what a district or state boundary is.

Rainfall anomalies in millimetres for 01-26 June. Greens/blues are above, browns/ochres are below. This section which includes Maharashtra, Madhya Pradesh, Chhattisgarh, Jharkhand, Bihar, Uttar Pradesh and part of Rajasthan shows how deficient areas are interspersed with excess areas. Watersheds could be the answer. Image source: NCEP, CPC

For everything that concerns water – which does mean everything that is essential to us: agriculture, forests, grassy regions and orchards, water that can be used for drinking, rural and urban settlements, commerce and industry – it is the group of hydrological structures we call a river basin (or sub-basin if the basin is a large one) that becomes the spatial region to study and plan for.

We have 36 states and union territories and also 36 meteorological divisions. These correspond with each other for most of the country and this correspondence, unnecessary and misleading, has led to our incorrect view of where rain falls and how it behaves where it falls. It has been a persistent error because I think of administrative inertia combined with the quite needless politics that surrounds river (or surface) and ground water.

Rain falls upon and rainwater collects and moves surface water then not in a taluka or district, but in a biophysical region which in one way we can describe as a river sub-basin or a large watershed. There are other pieces that make the whole: type of soil, the underlying geological strata, the mix of vegetation, the density and health of forests, the mix of cultivated crops, and the spread and density of human settlements (which use and alter these pieces).

Rainfall as estimated by Insat-3D and mapped in daily images for 14-28 June 2016. The background is the major river basins, not states (click for 386kb full res). The IMD’s RAPID system has this monsoon introduced river basins as a base map. Images source: IMD/ISRO RAPID

Table of river basins and sub-basins with sizes. Source: WRIS

We know which our major rivers are, and those of us who are curious enough about the biophysical pieces that determine the characteristics of the regions in which we live also know the names of lesser rivers. How many river sub-basins are there in Bharat?

There are several answers because there have been (and continue to be) several authorities whose work it is to assess and measure water. Their methodologies differ somewhat each from the other, and that is why they not only give us differing numbers of major river basins but also – for those basins whose names are the same – differing sizes for a single river basin.

The Water Resources Information System (WRIS) which is the newest methodical system and which has come about because of our remote sensing expertise, has the most detailed information about our river basins. There are also the Central Water Commission, the National Commission for Integrated Water Resources Development Plan, the All India Soil and Land Use Survey, and the Central Ground Water Board.

Depending on their thematic orientation, these have (in their early forms which date back to the late 1940s) conducted detailed surveys of river basins and districts, outlined hydrological units, catchment zones, river valley projects, watersheds and have through such mechanisms steered (at times forced) states into recognising that river basins are at least as important as state boundaries.

How many are there? The WRIS informs us that there are 26 river basins and 102 sub-basins. Thus there are about three times as many sub-basins as there are states (and UTs) and there is one sub-basin for about every six districts. The biggest river basins are those of the Ganga (808,334 square kilometres), the Indus (till the border, 453,931 sq km), Godavari (302,063 sq km) and Krishna (254,743 sq km). The 102 sub-basins have a median size (excluding the very smallest) of 29,200 sq km and range from 1,676 sq km to 99,040 sq km for the Brahmaputra Upper and 125,084 sq km for the Yamuna Lower basins. The larger sub-basins (there are 14 whose geographic sizes are more than 50,000 sq km) contain dozens of watersheds each (there are some 3,200 in Bharat).

In the small hydrological units that we call watersheds, and in the larger ones we call sub-basins and river basins, is where the rain falls and where it needs to be measured and counted. This our earth sciences agencies already do. It is up to us and up to administrators of districts, states and particularly of all Class I and larger cities to alter the manner in which we look at the water that falls in this wondrous season upon our earth.

— Rahul Goswami

A race between monsoon and water

June 1, 2016 by Climate portal editor Leave a Comment

The southern states of Tamil Nadu, Karnataka, Andhra Pradesh and Telengana are in dire need of rainwater to replenish exceedingly low levels in reservoirs and all surface water structures. This water has come in the form of showers over the past five or six days, although the spread of the rainfall has been patchy, and whether rainwater has collected in significant quantities and percolated into sub-soil aquifers will not be known for at least another week.

Until 31 May 2016 the stored water situation as measured by the quantities recorded in the 91 major reservoirs of India was very grave indeed. The most recent weekly bulletin of the Central Water Commission, which monitors what is called the ‘live storage status’ of the 91 major reservoirs, was issued on 26 May. Out of the 91 reservoirs, 37 have hydro-electric power plants which deliver electricity to the states in which these reservoirs are and to the national grid.

The total ‘live storage’ capacity of these 91 reservoirs is 157.799 billion cubic metres (BCM) which is estimated as being about 62% of the total storage capacity of 253.388 BCM that is estimated to have been built or created. But the 26 May bulletin placed the total storage available in these reservoirs at 26.816 BCM, which is 17% of the total of 91 reservoirs. At this time in 2015, the total stored water was 49.119 BCM and the average of the last 10 years of storage at this time was 33.764 BCM. Thus, the stored water for the week ended 26 May is 55% of the quantity stored in 2015 and 79% of the quantity stored at this time averaged for the last ten years.

The Northern region is Himachal Pradesh, Punjab and Rajasthan. There are six reservoirs with total live storage capacity of 18.01 BCM. By 26 May the total storage in these reservoirs was 3.91 BCM which is 22% of the total live storage capacity. The stored volume at the corresponding period in 2015 was 43% and the stored volume of the average corresponding period of the last ten years was 29%.

The Eastern region is Jharkhand, Odisha, West Bengal and Tripura. There are 15 reservoirs with total live storage capacity of 18.83 BCM. By 26 May the total live storage in these reservoirs was 4.22 BCM which is 22% of total live storage capacity. The stored volume at the corresponding period in 2015 was 34% and the stored volume of the average corresponding period of the last ten years was 20%.

The Western region is Gujarat and Maharashtra. There are 27 reservoirs with total live storage capacity of 27.07 BCM. By 26 May the total live storage in these reservoirs was 3.90 BCM which is 14% of total live storage capacity. The stored volume at the corresponding period in 2015 was 26% and the stored volume of the average corresponding period of the last ten years was also 26%.

The Central region is Uttar Pradesh, Uttarakhand, Madhya Pradesh and Chhattisgarh. There are 12 reservoirs with total live storage capacity of 42.30 BCM. By 26 May the total live storage available in these reservoirs is 9.59 BCM which is 23% of total live storage capacity. The stored volume at the corresponding period in 2015 was 33% and the stored volume of the average corresponding period of the last ten years was 18%.

The Southern region is Andhra Pradesh, Telengana, combined projects in both states, Karnataka, Kerala and Tamil Nadu. There are 31 reservoirs with total live storage capacity of 51.59 BCM. By 26 May the total live storage available in these reservoirs was 5.21 BCM which is 10% of total live storage capacity. The stored volume at the corresponding period in 2015 was 27% and the stored volume of the average corresponding period of the last ten years was 20%.

Monsoon outlook for June and July

May 29, 2016 by Climate portal editor Leave a Comment

At the end of May 2016, based on a reading of the seasonal forecasts of our Earth System Science Organisation group (under the Ministry of Earth Sciences) and complemented by the collaborative seasonal forecasts of the NOAA Center for Weather and Climate Prediction, we have prepared an outlook for the June and July monsoon 2016 months.

The regional rainfall outlook for June and July 2016. Green hues are +0.25 to +1mm/day averaged over the outlook period.

The outlook shows: (1) that our main concern of whether the first stage monsoon forecast of the IMD remains true is fulfilled, which is, that the 2016 monsoon will be normal (and better than normal in some regions); (2) that our next most important concern of whether any region will have significantly below normal rainfall is also addressed, and under the current forecasts there is no such region; (3) that the June and July rains will be at least normal in most states and meteorological sub-divisions.

Some provisos need to be observed. The seasonal forecasts are released for three month spells (May to July, June to August, and so on). Depending on the kind of modelling that is followed (and there are several) the outlooks are updated or modified every 10 days to fortnightly to monthly. These updates are based on what are called ‘initial conditions’ which for our current outlook is the first half of May.

Here is a more detailed regional outlook for June and July 2016:
• Tamil Nadu and Kerala will have rain that over the season is +1 to +1.25mm/day.
• Karnataka, Andhra Pradesh and Telengana, Madhya Pradesh, most of Maharashtra, all the states of northern and north-west India, Uttar Pradesh and Bihar, Sikkim, Arunachal, lower Assam, western Meghalaya, and Lakshadweep will have rain that that over the season is +0.25 to +1 mm/day.
• Odisha, Chhattisgarh, southern Jharkhand, gangetic West Bengal, eastern Vidarbha (Maharashtra), the north-eastern half of Telengana, north coastal Andhra Pradesh, upper Assam, Nagaland, Manipur, Mizoram and Tripura will have rain that over the season is -0.2 to +0.25mm/day and Andaman and Nicobar islands will have rain that is up to -0.5 mm/day.

This outlook we will amend between June 10 and 15 as the ESSO’s forecasts and international collaborative monsoon forecasts are updated.

A tribute to the weathermen of Bharat

April 12, 2016 by Climate portal editor 9 Comments

When the weather causes anxiety, in the districts and towns, harassed administrators and the impatient public turn quickly to the weatherman. Whether for advice about a possible heat wave, about thunderstorms or hail storms, about extended dry spells, about the possibility of rainfall during a crop sowing period one week distant, it is the local weatherman who has the knowledge and provides the answers.

That weatherman – and weatherwoman, for the service has a number of women scientists – is from the India Meteorological Department, the weather watchers for Bharat.

Theirs is often a thankless task, of poring over the output from instruments and computations, ensuring that the essential information about weather conditions six, 12 or 24 hours hence is transmitted to all those to whom it matters.

Our weathermen scan the skies with their instruments so that they can issue, to airports and airfields all over Bharat, the ‘meteorological aerodrome report’ (or METARs) on which all our commercial flights depend. Our weathermen scan the seas with their instruments to issue the sea weather reports and fleet forecasts for marine traffic in the Arabian Sea, the Bay of Bengal, the Andaman Sea and the nearer Indian Ocean.

India Climate portal thanks readers for the appreciative responses to this tribute, and for the comments (below) which we urge the Ministry of Earth Sciences to consider.

Our weathermen scan the atmosphere with the aid of the orbital eyes of our satellites so that, for every single district, an agricultural meteorology forecast is issued every day and for every crop season. Our weathermen scan the routes of the Indian Railway system, the largest and most heavily utilised in the world, for threatening weather conditions that would affect the running of trains. They do this every single day, round the clock.

Today the India Meteorological Department has issued its first forecast for the 2016 monsoon, the Indian summer monsoon, whose patterns have been so well known for all our recorded history. It is a forecast that has been impatiently awaited this year, because of the shortages of water in our river basins, because of the likelihood – as ever – of heat waves, and because we have been so very worried about whether we will get the rains that eluded Bharat in 2015 and 2014.

The short answer is: yes we will. The details of the percentages, the probabilities, the averages, the likely ranges and other ponderables are all over the news. We’d like to compliment the people behind the forecast.

We sincerely thank the women and men of the India Meteorological Department for their extraordinary efforts – every day, week, season and year – to serve us. The IMD today provides us, in the public domain, through the internet, via television, with the help of mobile phone messages, and through smartphone apps, an array of weather services. These scientists, administrators, technicians and field staff have worked as hard to make this range of services available to us as they have worked to understand our ‘mausam’ better. Theirs is a science whose complexity defies the most powerful computing systems available, and they translate what they see into language that guides us as we go about our daily routines. It calls for a breadth of skills that must be applauded.

A sense of history and philosophy guides their work. The scientists and technicians of the Department take as much inspiration from the Upanishads (which contain serious discussion about the processes of cloud formation, rain, and the seasonal cycles) and from Varahamihira’s classical work, the Brihatsamhita, as they do from the insights that they collaborate on today in what is known as earth systems science. It is a remarkable legacy that is very much alive in the offices and field stations of the IMD.

For their work, and as representatives of the widely distributed IMD network of staff, we thank:
Director General of Meteorology, Laxman Singh Rathore; Additional Director General of Meteorology (Research), Bishwajit Mukhopadhyay; Deputy Director General of Meteorology (Upper Air Instruments), Devendra Pradhan; Deputy Director General of Meteorology (Surface Instruments), Rajesh Ramdas Mali; Deputy Director General of Meteorology, Regional Meteorological Centre New Delhi, Anand Kumar Sharma; Deputy Director General of Meteorology, Regional Meteorological Centre Mumbai, K S Hosalikar; Deputy Director General of Meteorology, Regional Meteorological Centre Kolkata, Gakul Chandra Debnath; Deputy Director General of Meteorology, Regional Meteorological Centre Chennai, S Bagulayan Thampi; Deputy Director General of Meteorology, Regional Meteorological Centre Guwahati, Sanjay Oneill Shaw; Deputy Director General of Meteorology, Regional Meteorological Centre Nagpur, P K Nandankar; Head, Agromet Services K K Singh; Deputy Director General of Meteorology, Satmet, New Delhi, Ashok Kumar Sharma; Deputy Director General of Meteorology, Hydromet, New Delhi, Surinder Kaur; Deputy Director General of Meteorology, Services, New Delhi, Brahma Prakash Yadav; Deputy Director General of Meteorology, Organisation, New Delhi, S D Attri; Deputy Director General of Meteorology, EMRC, New Delhi, Sunil Kumar Peshin; and Deputy Director General of Meteorology, Numerical Weather Prediction, New Delhi, Swapan Kumar Roy Bhowmik. Thank you all for a job very well done indeed.

Rahul Goswami

Normal to good monsoon likely

April 10, 2016 by Climate portal editor 1 Comment

The Indian summer monsoon in 2016 for the months of June to September will be normal to above normal in almost all the meteorological sub-divisions.

This is our reading of the seasonal climatic predictions provided by five different sources, amongst them the India Meteorological Department (IMD), which themselves are based on ensembles of forecasts.

Our outlook for the June to September 2016 period is based on an initial study of the three-monthly and seasonal predictions which are in the public domain, from the following agencies:

A mapping of the forecast by one predictive climate model, for the May to July period. Source: NOAA/NCEP

The Climate Prediction and Monitoring Group of the India Meteorological Department (IMD), Ministry of Earth Sciences, Government of India; the Climate Forecast System Version 2 (CFSv2) by the Climate Prediction Center of the National Centers for Environmental Prediction (NCEP), USA; regionalised Multi-Model Ensemble (NMME) forecasts from the Climate Prediction Center which are based on models of the NOAA and NASA; and the Meteorological ‘Met’ Office of Britain which is a World Meteorological Organisation climate research centre.

Combining the indications from this early set of forecasts we see that when typical monsoon conditions have set in over southern and peninsular India, the June and July rainfall patterns should be normal for June with an increase in average rainfall for July (in the southern peninsula, the west coast, north-eastern states and the north India mountainous states). The models currently also point to the August and September period recording above normal rainfall over most of India, and normal rainfall in central India.

The climatic prediction models whose forecasting products we have examined make their predictions for 90-day periods (such as May, June and July together) based on conditions observed and calculated for a given month (January, February and March so far). We will consolidate and expand the scope of this initial prognosis – which is of a normal to above normal monsoon – as these forecasts are updated.