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Marathi Article about Prof R R Kelkar by Shailesh Malode

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लहरी हवामानाचा अचूक वेध

लेखक – शैलेश माळोदे, नाशिक

डॉ. रंजन केळकर, हवामानतज्ञ. हवामान खात्यातील प्रदिर्घ योगदानानंतर आताही त्यांचे महाराष्ट्रातील हवामानाविषयी संशोधन सुरुच आहे.

‘महाराष्ट्राचे हवामान’ हे माझं पुस्तक मी लिहू शकलो म्हणून मी परमेश्वराचे उपकार स्मरण करतो असं स्पष्टपणे प्रस्तावनेत नमूद करून वैज्ञानिक म्हणून परमेश्वराच्या अस्तित्वाविषयी निःसंदिग्धपणे आणि अत्यंत नम्रपणे आपल्या विविध मर्यादांची जाणीव बाळगत आपल्या ख्रिस्ती असल्याबद्दल कुठलाही खोटा अभिनिवेश न ठेवता डॉ. रंजन केळकर यांनी अगदी दिलखुलासपणे स्वतःचा जीवनपट माझ्याबरोबर उलगडला. डॉ. रंजन केळकर हे 1998 ते 2003 या काळात हिंदुस्थानी हवामान खात्याचे महासंचालक होते. प्रा. डॉ. रंजन केळकर हवामानविषयक तज्ञ तर आहेतच, पण त्यांनी सोप्या भाषेत हवामानविषयक लेखन पुस्तकं, लेख, ब्लॉग व्याख्यानं याद्वारे केलेय. विशेषतः निवृत्तीनंतर. प्रयत्नपूर्वक त्यांनी लोकांना समजेल अशा पद्धतीनं आपली लेखनशैली विकसित केलीय.

हवामानशास्त्र विभागात पुणे आणि नवी दिल्ली येथे त्यांनी 38 वर्षे काम केलं. ‘माझं पुरं आयुष्य मी या विषयाला आणि विभागाला दिलं असं म्हटलं तर वावगं ठरणार नाही. 31 डिसेंबर 2003 रोजी सेवानिवृत्त झाल्यावर मी महाराष्ट्रात परतायचं ठरवलं. 2004 ते 2008 च्यादरम्यान मी पुणे विद्यापीठात इस्रो अध्यासनावर मानद प्राध्यापक होतो आणि उपग्रह हवामानशास्त्र हा विषय मी पदव्युत्तर विद्यार्थ्यांना शिकवला असे सांगत डॉ. रंजन केळकर यांनी त्यांच्यामधील शिक्षणाचा पैलूही खुला केला. 19 डिसेंबर 1943 रोजी मुंबईच्या शिवाजी पार्क भागात त्यांचा जन्म झाला. त्यांचं सुरुवातीचं शिक्षण बालमोहन विद्यामंदिर, मुंबई आणि नंतरचे शालेय शिक्षण सेंट जॉन्स सेकंडरी स्कूल, पुणे इथे झालं. त्यांचे वडील पोस्टात नोकरीला होते. केळकर मूळचे अलिबागचे. या ठिकाणी असलेली चुंबकीय वेधशाळा ब्रिटिशांनी 1900 च्या दशकात उभारली. खरं तर विविध निरीक्षणे चांगल्या प्रकारे नोंदवता यावीत म्हणून ही वेधशाळा मुंबईतील कुलाब्याहून हलविण्यात आली होती. त्याकरिता तिथे वीजदेखील पुरविण्यात आली नव्हती. वेधशाळेच्या समोर राहणाऱ्या केळकर कुटुंबीयांना  वीज नसल्याची सवय आणि वेधशाळेचं अप्रूप होतं.  त्यामुळे डॉ. रंजन केळकर हवामान खात्यामध्ये नोकरीला लागले ही एक प्रकारे आनंदाची बाब होती. निदान त्यांच्या वडिलांसाठी,शिक्षण पूर्ण झाल्यावरउष्णदेशीय हवामानशास्त्र (आयटीएम- आताची आयआयटीएम) संस्था, पुणे येथे 1964 साली अराजपत्रित अधिकारी दर्जाच्या संशोधन सहायक पदावर नोकरी मिळाली.  डॉ.केळकर यांची कारकीर्द शास्त्रीय प्रवाहात फुलली.

नोकरी करत असतानाच त्यांनी पुणे विद्यापीठातून पीएच.डी. प्राप्त केली. त्यांच्या प्रबंधाचा विषय वातावरणीय शास्त्राशी निगडित आणि आता प्रचंड चर्चेत असलेल्या ग्लोबल वॉर्मिंगशी संबंधित होता. कार्बन डायऑक्साईडचे प्रमाण वाढल्यामुळे पृथ्वीच्या पृष्ठभागावरील तापमान वाढते असे त्यांनी संशोधनातून दाखवून  दिले.

आयबीएमचे सहा संगणक 1960 च्या उत्तरार्धात देशाला देण्यात आले होते. त्यापैकी एक आयटीएममध्ये होता. त्याविषयी डॉ. केळकर यांनी प्रयत्नपूर्वक सर्व शिकून घेतले. 1970 मध्ये यासाठीच त्यांना भारतीय हवामानशास्त्र खात्यात पुण्यातील सिमला हाऊसमध्ये ‘कृषी हवामानशास्त्र’ या विषयासाठी विशेषज्ञ म्हणून बढतीवर नेमण्यात आले. 1980 पर्यंत ते या विषयात कार्य संशोधन आणि अंदाज या दोहोंबाबत करत राहिले. 1980 मध्ये ‘इन्सॅट-1ए’ हा उपग्रह हिंदुस्थानतर्फे सोडण्यात आला. त्याद्वारे प्राप्त आकडेवारीचे विश्लेषण करून हवामान अंदाज व्यक्त करण्यासाठीच्या गटात डॉ. केळकर यांची निवड झाली.

सहा प्रदीर्घ वर्षे त्यांनी हवामान खात्याचे महासंचालक म्हणून कार्यभार सांभाळला. सात बढत्या मिळवून ते या पदी पोहोचले. हिंदुस्थानमध्ये डॉप्लर रडार्सचा वापर माझ्या महासंचालक पदाच्या कारकीर्दीत सुरू झाला.’’ 1999 मध्ये ओडिशात महाचक्रीवादळ झालं. त्यात दहा हजारांपेक्षा जास्त लोकांचा मृत्यू झाला. डॉ. केळकर म्हणतात, ‘खात्यानं अंदाज बरोबर व्यक्त केला होता, पण आपल्याकडे तो लोकांपर्यंत पोहोचविण्यासाठी दळणवळण यंत्रणा आणि हलवाहलवीच्या सुविधांचा अभाव होता. त्यानंतर सरकारने त्याबाबत ठोस पावलं उचलली. राष्ट्रीय आपत्ती व्यवस्थापन प्राधिकरण आणि एनडीआरएफची निर्मिती झाली. केळकर यांच्या कारकीर्दीतच 2001 चा भूज येथील प्रलयकारी भूकंप झाला. त्यानंतर त्यांनी भूकंपशास्त्रीय अद्ययावतीकरण करून पाच मिनिटांच्या आत नेमकी स्थिती कळवणारी यंत्रणा तयार झाली. गोवारीकर मॉडेल 2002 मध्ये विफल ठरल्यावर केळकर यांनी डायनॅमिक मॉडेल या संस्थेने मॉडेलच्या जागी प्रस्थापित करण्यात महत्त्वाची भूमिका बजावली.

आज निवृत्त झाल्यावरदेखील डॉ. रंजन केळकर हवामानशास्त्रविषयक विपुल लेखन आणि प्रबोधन करतात. त्यांनी एकूण आठ पुस्तके इंग्रजी आणि मराठीतून प्रकाशित केली आहेत. एका विशेष प्रकारच्या शांतीचा अनुभव घेत डॉ. केळकर यांचा जीवनक्रम सुरू आहे. तो एक आदर्श म्हणायला हवा.

Prof R R Kelkar’s New Book on “Weather Satellites”

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Prof R R Kelkar’s new book on “Weather Satellites” has been co-published by BSP Books, Hyderabad, and the Indian Meteorological Society, New Delhi. Click on the link below for details.

http://bspublications.net/book_detail.php?bid=1372

“Satellite Meteorology” Second Edition

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sat-met-2-cover

Prof R R Kelkar’s book “Satellite Meteorology” Second Edition is now available.  

View table of contents, text of first chapter, author’s biodata and other details on the web site of the publishers BS Publications

Order the book from the co-publishers CRC Press

Buy the book from amazon.in

Second Edition of “Satellite Meteorology”

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SatMet Book Cover 2

My first book “Satellite Meteorology” was published in 2006. The publishers, BSP Books of Hyderabad, India, feel that is now time to bring out a second edition and they have invited me to write a more contemporary version of the text.

Some of my blog readers may have read the book and I would be grateful if they send me their comments and suggestions which I can incorporate in my revision, with due acknowledgement of course. If they wish to send me any literature or references, my email id is kelkar_rr@yahoo.com.

– R. R. Kelkar

 

Italian Court Sentences Geoscientists to Imprisonment

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As per a news item in the Indian Express dated 23 October 2012, an Italian court convicted seven people to six years’ imprisonment for failing to give warnings of a 6.3 magnitude earthquake that killed more than 300 people in central Italy on 6 April 2009. Those convicted were prominent seismologists, geologists and disaster experts. They were accused of giving inexact, incomplete and contradictory information and ignoring the small tremors felt by local residents prior to the earthquake.

The verdict is sure to be challenged in a higher court and the accused may eventually be acquitted. However, it raises important and fundamental issues, legal, ethical and professional. In many countries including India, operational aspects of seismology and meteorology are handled by a single official agency, so the issues are common to both the branches of geoscience.

Most meteorological agencies the world over are run by the government with public funding, although they do earn a little by charging for some of their services. The scientists who work for them are therefore accountable and responsible to the public.

Compared to the simple things they had a century ago, meteorologists now have million-dollar supercomputers, models and satellites at their disposal and these are all funded by the public. And yet, there has been no visible quantum jump in the science or the forecasts. Meteorologists have always been the subject of jokes and cartoons, but that apart, today’s public is not an admirer of the meteorological services, to say it softly. People are certainly going to be increasingly demanding in future and would expect value for money. In a sense, the Italian court verdict should be considered as some indicator of current public thinking about the inadequacy of services, both in seismology and meteorology.

Some of the sins of commission and omission of which meteorologists can be found guilty are the following:

overprediction or raising a scare,

underprediction or keeping a low profile,

using incomprehensible language,

covering a wide range of possible situations to reduce the chances of going wrong,

making bold statements when the confidence level is low,

not taking a clear stand even when the confidence level is high,

not taking the blame for wrong forecasts, but blaming the weather itself for not behaving well,

speculating about so distant a future that nobody alive today will be able to verify.

The court verdict should be a cause for introspection…!

Megha-Tropiques: The Weather Satellite with a Difference

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The Megha-Tropiques satellite has been lauched into an orbit that has a very low inclination of 20 degrees. It is not strictly an equatorial orbit but quite nearly so. The height of the satellite is 866 km and the swath or the north-south extent of the coverage is 1700-2200 km wide. The period of revolution is 102 minutes. The repetivity is 6 times a day over a large part of the tropical belt and 4-5 times a day at higher latitudes. The satellite has four payloads that would help estimate oceanic winds, rainfall, temperature and humidity profiles, total water vapour, cloud liquid water, cloud ice and several radiation budget parameters, all from a common platform.

Since 1982, the Indian Space Research Organisation has launched a series of geostationary satellites that have provided a continuous meteorological coverage of the Indian region and the surrounding land and Indian Ocean regions. Four satellites in the INSAT-1 series, three in the INSAT-2 series, the dedicated Kalpana-1 satellite, and the current INSAT-3A satellite, have carried a total of nine VHRR instruments so far, besides the CCD cameras on the more recent satellites. The next satellite, INSAT-3D, to be launched soon, will have an advanced 6-channel imager and a 19-channel sounder. However, these satellites have primarily been designed towards meeting the requirements of operational meteorology in India.

Megha-Tropiques is the first satellite of the Indian space programme that makes a welcome departure from this philosophy. It is going to make systematic observations of parameters related to climate studies and its sensor configuration is entirely different from the INSAT payloads. Geostationary satellites, because they have to be parked at a height of 36,000 km above the earth’s surface, are not suited for microwave remote sensing as the radiance reaching them is very weak. Megha-Tropiques being in a low altitude orbit is designed to make microwave measurements and it carries two microwave payloads.

Megha-Tropiques is a joint India-France (ISRO-CNES) mission with a shared responsibility for development of payloads as well as launch. The spacecraft was launched by ISRO with its Polar Satellite Launch Vehicle (Flight PSLV-C18) from Shriharikota on 12 October 2011. The expected mission life is 3 years.

The main scientific objectives of the Megha-Tropiques mission are:

(a) To collect a long-term set of measurements with a good sampling and coverage over tropical latitudes to understand better the processes related to tropical convective systems and their life cycle.

(b) To improve the determination of atmospheric energy and water budget in the tropical region on various time and space scales.

(c) To study tropical weather and climate events like monsoon variability, droughts, floods, and tropical cyclones, and their predictabilty.

Megha-Tropiques carries a rare combination of three state-of-art payloads, MADRAS, SAPHIR and ScaRaB designed for measurements of radiative fluxes, precipitation, humidity profiles and cloud properties.

MADRAS (Microwave Analysis and Detection of Rain and Atmospheric Structures), is a passive imaging radiometer operating at five frequencies of 18.7, 23.8, 36.5, 89 and 157 GHz in both H and V polarizations except the 23.8 GHz which has only V polarization. Data from the first three channels has applications in the retrieval of rain over oceanic regions, liquid water content in clouds and vertical integrated water vapour. Their spatial resolution is 40 km. The 89 GHz channel is useful for retrieving convective rainfall over both land and ocean at a resolution of less than 10 km. The 157 GHz channel is meant for measuring the concentration of ice particles in clouds at a resolution as high as 6 km.

SAPHIR (Sounder for Atmospheric Profiling of Humidity in the Inter-tropics by Radiometry) is a microwave sounding instrument. It has six channels in the frequency region of 183 GHz, all having 10 km ground resolution. SAPHIR data will be used to retrieve atmospheric humidity profiles at six levels up to a height of 12 km. After INSAT-3D is launched, SAPHIR soundings will complement the temperature and humidity profiles that will be derived from the INSAT-3D sounder.

ScaRaB (Scanner for Radiation Budget Measurement) is the third Megha-Tropiques payload. It has four channels: Sc1 – Visible (0.5-0.7 µ), Sc2 – Solar (0.2-4.0 µ), Sc3 – Total (0.2-100 µ), and Sc4 – IR Window (10.5-12.5 µ). Sc2 and Sc3 are the main channels of the ScaRaB instrument. ScaRaB will measure fluxes at the top of the atmosphere with a ground resolution of 40 km. Longwave irradiance can be calculated from the difference between Sc3 and Sc2 measurements. Images from Sc1 and Sc4 channels will be used for scene identification and will provide the necessary compatibility with operational satellites like INSAT which have radiometers with similar spectral channels.

The MADRAS payload has been developed jointly by ISRO and CNES France, while SAPHIR and ScaRaB have been developed by CNES. ROSA (GPS Radio Occultation Sensor) is another payload that Megha-Tropiques is flying. This has been procured by ISRO from Italy. ROSA operates at L1 and L2 frequencies of 1575.42 and 1227.60 MHz and will be used for retrieving temperature and humidity profiles in the atmosphere by the GPS occultation method.

India launched the Oceansat-2 satellite on 23 September 2009, which has an on-board Ku-band scatterometer for measurement of surface winds and is already providing useful data on the global oceans. The launch of INSAT-3D with its advanced imager and sounder, is now eagerly awaited. A synergistic utilization of the data gathered from all these satellites is certainly going to lead to a great advancement of the current knowledge of the role of the tropical atmosphere and oceans in the global weather and climate.

The progress of the Megha-Tropiques mission can be seen on the web sites http://meghatropiques.ipsl.polytechnique.fr/ and http://www.isro.org/

Megha-Tropiques Launched in an Orbit Conceptualised in 1982

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Today’s successful launch of the Megha-Tropiques satellite by ISRO takes my thoughts back to 1982. The first of the INSAT series of satellites, INSAT-1A, had been sent into geostationary orbit and I had just published my first research paper in satellite meteorology.

The paper was entitled “A conception of an equatorial orbiting meteorological satellite for the tropics”. I had Sant Prasad as my first coauthor and P. N. Khanna, who is now no more, was the second coauthor. I still remember that the referee had been reluctant to accept the paper for publication but had later relented with the condition that the paper be shortened to the minimum length possible. It was eventually published as a two-page letter to the editor (Mausam, 1982, vol. 33, no. 4, pp. 507-508).

In 1982, there were two distinct classes of meteorological satellites, polar orbiting and geostationary. Each of them had their advantages and disadvantages. The polar orbiting satellites obviously viewed the poles in every orbit, but they passed over any place on the equator only twice in 24 hours. Geostationary satellites were positioned relatively over a place on the equator at 36,000 km height from where they could scan a large part of the earth every 30 minutes. They were good for the tropics but could not see the poles.

My 1982 paper conceived of a different type of orbit that was a mix of the two. The orbit suggested was an equatorial orbit but the satellite was not to be at the geostationary height but at the height of a polar orbiter. This would enable the satellite to view the entire tropical belt during its revolution around the earth’s axis. Several such views of the entire tropical region would be generated during a 24-hour period. The north-south extent of the tropical belt and the repeat cycle could be designed as required just through a proper choice of the satellite height.

I still like this little paper of mine, not only because it was my first in satellite meteorology, but more so because in 1982 it was only an idea. I had no way of proving that it worked. It is only today, in 2011, that I have seen that it really works.

The MeghaTropiques satellite has been lauched by ISRO into an orbit that has a very low inclination of 20 degrees. It is not strictly an equatorial orbit but quite nearly so. The satellite is at a height of 866 km and the swath or the north-south extent of the coverage is 1700-2200 km wide. The period of revolution is 102 minutes and the repitivity is 6 times a day over a large part of the tropical belt and 4-5 times a day at higher latitudes. The satellite has four payloads that would help estimate oceanic winds, rainfall, temperature and humidity profiles, total water vapour, cloud liquid water, cloud ice, and radiation budget parameters, all from a common platform.


 

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