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Singh, Narendra
- ARIES, Nainital:A Strategically Important Location for Climate Change Studies in the Central Gangetic Himalayan Region
Abstract Views :436 |
PDF Views:165
Authors
Affiliations
1 Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263 002, IN
1 Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263 002, IN
Source
Current Science, Vol 109, No 4 (2015), Pagination: 703-715Abstract
ARIES, acronym for Aryabhatta Research Institute of Observational Sciences, located in the Central Gangetic Himalayan (CGH) region is emerging as one of the unique sites for climate change studies. The long-term, in situ, precise measurements of aerosols and trace gases obtained from this region provide valuable inputs for climate studies. Atmospheric scientists from ARIES are actively involved in nearsurface measurements for meteorology, aerosols and trace gases as well as vertical profiling. The Institute is also providing the observational infrastructure and research support to three major projects of the Indian Space Research Organization, Geosphere Biosphere Programme, which basically deals with the measurement of aerosols, trace gases and boundary-layer experiments. The upcoming stratosphere-troposphere radar and high-power micro-pulse lidar observational facilities will be utilized for the continuous vertical profiling of winds, aerosol and cloud properties at a very fine resolution in time and space. Apart from this, atmospheric scientists of ARIES also have active national and international research collaborations. The important results obtained from these research activities are highlighted and upcoming major observational facilities in the field of atmospheric sciences are discussed. They clearly demonstrate the importance of the unique geographical location of ARIES for climate change studies in the CGH region. These measurements and routine meteorological observations provide the necessary atmospheric corrections to the astrophysical observations taken using optical telescopes located at the site.Keywords
Aerosols, Air Pollution, Climate Change, Trace Gases, Wind Profiler.- Variations in the Cloud-Base Height over the Central Himalayas during GVAX:Association with the Monsoon Rainfall
Abstract Views :435 |
PDF Views:173
Authors
Narendra Singh
1,
Raman Solanki
1,
N. Ojha
2,
M. Naja
1,
U. C. Dumka
1,
D. V. Phanikumar
1,
Ram Sagar
1,
S. K. Satheesh
3,
K. Krishna Moorthy
4,
V. R. Kotamarthi
5,
S. K. Dhaka
6
Affiliations
1 Aryabhatta Research Institute of Observational Sciences, Nainital 263 002, IN
2 Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz, DE
3 Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bengaluru 560 012, IN
4 ISRO Head Quarters, Bengaluru 560 231, IN
5 Environmental Science Division, Argonne National Laboratory, Illinois, US
6 Radio and Atmospheric Physics Lab., Rajdhani College, University of Delhi, Delhi 110 015, IN
1 Aryabhatta Research Institute of Observational Sciences, Nainital 263 002, IN
2 Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz, DE
3 Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bengaluru 560 012, IN
4 ISRO Head Quarters, Bengaluru 560 231, IN
5 Environmental Science Division, Argonne National Laboratory, Illinois, US
6 Radio and Atmospheric Physics Lab., Rajdhani College, University of Delhi, Delhi 110 015, IN
Source
Current Science, Vol 111, No 1 (2016), Pagination: 109-116Abstract
We present the measurements of cloud-base height variations over Aryabhatta Research Institute of Observational Science, Nainital (79.45°E, 29.37°N, 1958 m amsl) obtained from Vaisala Ceilometer, during the nearly year-long Ganges Valley Aerosol Experiment (GVAX). The cloud-base measurements are analysed in conjunction with collocated measurements of rainfall, to study the possible contributions from different cloud types to the observed monsoonal rainfall during June to September 2011. The summer monsoon of 2011 was a normal monsoon year with total accumulated rainfall of 1035.8 mm during June-September with a maximum during July (367.0 mm) and minimum during September (222.3 mm). The annual mean monsoon rainfall over Nainital is 1440 ± 430 mm. The total rainfall measured during other months (October 2011-March 2012) was only 9% of that observed during the summer monsoon. The first cloud-base height varied from about 31 m above ground level (AGL) to a maximum of 7.6 km AGL during the summer monsoon period of 2011. It is found that about 70% of the total rain is observed only when the first cloud-base height varies between surface and 2 km AGL, indicating that most of the rainfall at high altitude stations such as Nainital is associated with stratiform low-level clouds. However, about 25% of the total rainfall is being contributed by clouds between 2 and 6 km. The occurrences of high-altitude cumulus clouds are observed to be only 2-4%. This study is an attempt to fill a major gap of measurements over the topographically complex and observationally sparse northern Indian region providing the evaluation data for atmospheric models and therefore, have implications towards the better predictions of monsoon rainfall and the weather components over this region.Keywords
Ceilometer, Central Himalaya, Cloud-Base, GVAX, Monsoon.- High-Frequency Vertical Profiling of Meteorological Parameters Using AMF1 Facility during RAWEX–GVAX at ARIES, Nainital
Abstract Views :386 |
PDF Views:179
Authors
Manish Naja
1,
Piyush Bhardwaj
1,
Narendra Singh
1,
Phani Kumar
1,
Rajesh Kumar
2,
N. Ojha
1,
Ram Sagar
3,
S. K. Satheesh
4,
K. Krishna Moorthy
5,
V. R. Kotamarthi
6
Affiliations
1 Aryabhatta Research Institute of Observational Sciences, Nainital 263 002, IN
2 National Center for Atmospheric Research, Boulder, Colorado, US
3 Indian Institute of Astrophysics, Bengaluru 560 034, IN
4 Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bengaluru 560 012, IN
5 Indian Space Research Organization, Head Quarters, Bengaluru 560 231, IN
6 Argonne National Laboratory, Argonne, IL, US
1 Aryabhatta Research Institute of Observational Sciences, Nainital 263 002, IN
2 National Center for Atmospheric Research, Boulder, Colorado, US
3 Indian Institute of Astrophysics, Bengaluru 560 034, IN
4 Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bengaluru 560 012, IN
5 Indian Space Research Organization, Head Quarters, Bengaluru 560 231, IN
6 Argonne National Laboratory, Argonne, IL, US
Source
Current Science, Vol 111, No 1 (2016), Pagination: 132-140Abstract
An extensive field study, RAWEX-GVAX, was carried out during a 10-month (June 2011-March 2012) campaign at ARIES, Nainital and observations on a wide range of parameters like physical and optical properties of aerosols, meteorological parameters and boundary layer evolution were made. This work presents results obtained from high-frequency (four launches per day), balloon-borne observations of meteorological parameters (pressure, temperature, relative humidity, wind speed and wind direction). These observations show wind speed as high as 84 m/s near the subtropical jet. It is shown that reanalysis wind speeds are in better agreement at 250 hPa (altitude of subtropical jet) than those above or below this value (100 hPa or 500 hPa). These observations also demonstrate that AIRS-derived temperature profiles are negatively biased in the lower altitude region, whereas they are positively biased near the tropopause. WRF simulated results are able to capture variations in temperature, humidity and wind speed profile reasonable well. WRF and AIRS-derived tropopause height, tropopause pressure and tropopause temperature also show agreement with radiosonde estimates.Keywords
Aerosols, Radiosonde, Subtropical Jet, Tropopause Folding, Vertical Profiling.- Detection of Solar Cycle Signal in the Tropospheric Temperature using COSMIC Data
Abstract Views :413 |
PDF Views:143
Authors
Affiliations
1 Radio and Atmospheric Physics Lab, Rajdhani College, University of Delhi, Delhi 110 015, IN
2 Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital 263 002, IN
3 Department of Applied Physics, Delhi Technical University, Delhi 110 042, IN
4 Department of Geophysics, Kyoto University, Kyoto 606850, IN
1 Radio and Atmospheric Physics Lab, Rajdhani College, University of Delhi, Delhi 110 015, IN
2 Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital 263 002, IN
3 Department of Applied Physics, Delhi Technical University, Delhi 110 042, IN
4 Department of Geophysics, Kyoto University, Kyoto 606850, IN
Source
Current Science, Vol 115, No 12 (2018), Pagination: 2232-2239Abstract
Influence of the solar cycle on temperature structure is examined using radio occultation measurements by COSMIC/FORMASAT-3 satellite. Observations from January 2007 to December 2015 comprising 3,764,728 occultations, which are uniformly spread over land and sea, have been used to study temperature changes mainly in the troposphere along with the solar cycle over 60°N–60°S geographic latitudes. It was a challenging task to identify the height at which the solar cycle signal could be observed in temperature perturbations as different atmospheric processes contribute towards temperature variability. Using a high spatial resolution dataset from COSMIC we are able to detect solar cycle signal in the zonal mean temperature profiles near surface at 2 km and upward. A consistent rise in the interannual variation of temperature was observed along with the solar cycle. The change in the temperature structure showed a latitudinal variation from southern to northern hemisphere over the period 2007–2015 with a significant positive influence of sunspot numbers in the solar cycle. It can be concluded that the solar cycle induces changes in temperature by as much as 1.5°C. However, solar cycle signal in the stratospheric region could not be identified as the region is dominated by large-scale dynamical motions like quasi-biennial oscillation which suppress the influence of solar signal on temperature perturbations due to its quasi-periodic nature.Keywords
Radio Occultation, Solar Cycle, Sunspot Number, Tropospheric Temperature.References
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