Refine your search
Collections
Co-Authors
Journals
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Chakraborty, Supriyo
- Estimation of Past Atmospheric Carbon Dioxide Levels using Tree-Ring Cellulose δ13C
Abstract Views :221 |
PDF Views:82
Authors
Affiliations
1 Indian Institute of Tropical Meteorology, Pune 411 008, IN
2 Physical Research Laboratory, Ahmedabad 380 009, IN
1 Indian Institute of Tropical Meteorology, Pune 411 008, IN
2 Physical Research Laboratory, Ahmedabad 380 009, IN
Source
Current Science, Vol 107, No 6 (2014), Pagination: 971-982Abstract
We study the applicability of the Farquhar model for carbon isotopic discrimination (change in carbon iso-topic composition from air CO2 to tree-ring cellulose) in C3 plants to trees growing in the field. Two new carbon isotope datasets from Himalayan conifers with published data from another eight sites across the world show disparate trends in the plot of carbon iso-tope discrimination versus atmospheric carbon dioxide concentration, in contrast to the model prediction of absence of any trend. This is because the model assumes that the tree adjusts its stomatal conductance for water-use efficiency to maintain a constant ratio of carbon dioxide concentrations inside and outside the leaf and treats the diffusive and biochemical fraction-ation factors as constants. By introducing a simple lin-ear dependence of these fractionation factors with ambient temperature and humidity, we have enhanced the applicability of the model to naturally growing trees. Further, despite the disparate trends exhibited by the 10 trees, we show using the inverse modelling that it is possible to derive a unique record of past atmospheric CO2 concentrations using tree cellulose δ13C data. The reconstructions also replicate the summer pCO2 gradient from tropics to mid-latitudes. We also discuss the merits and demerits of the model, and compare the model-derived pCO2 with that of the ice core-based records from Law Dome.Keywords
Atmospheric Carbon Dioxide, Carbon Iso-Tope, Cellulose, Climate Change, Tree Ring.Full Text
- Impact of Ecosystem Respiration on Carbon Balance in a Semi-Evergreen Forest of Northeast India
Abstract Views :229 |
PDF Views:73
Authors
Affiliations
1 Department of Environmental Science, Tezpur University, Tezpur 784 028, IN
2 Indian Institute of Tropical Meteorology, Pune 411 008, IN
3 Savitribai Phule Pune University, Pune 411 007, IN
4 Prince of Wales Institute of Engineering and Technology, Jorhat 785 001, IN
1 Department of Environmental Science, Tezpur University, Tezpur 784 028, IN
2 Indian Institute of Tropical Meteorology, Pune 411 008, IN
3 Savitribai Phule Pune University, Pune 411 007, IN
4 Prince of Wales Institute of Engineering and Technology, Jorhat 785 001, IN
Source
Current Science, Vol 116, No 5 (2019), Pagination: 751-757Abstract
We have estimated in this study the annual net ecosystem productivity (NEP) of Kaziranga National Park by using real-time eddy covariance data. We partitioned the net CO2 flux into gross primary productivity and ecosystem respiration (Re) using standardized method. Estimated annual NEP of the ecosystem 92.93 ± 1.7 g C m–2 year–1 indicated that the forest is a moderate sink of CO2 and is reported for the first time from a forest of Northeast India.Keywords
Eddy Covariance, Gross Primary Productivity, Net Ecosystem Productivity.Full Text
References
- Bhattacharyya, P., Neogi, S., Roy, K. S. and Rao, K. S., Gross primary production, ecosystem respiration and net ecosystem exchange in Asian rice paddy: an eddy covariance-based approach. Curr. Sci., 2013, 104(1), 67–75.
- Magnani, F. et al., The human footprint in the carbon cycle of temperate and boreal forests. Nature, 2007, 447, 848–850.
- Beer, C. et al., Terrestrial gross carbon dioxide uptake: Global distribution and covariation with climate. Science, 2010, 329, 834– 838.
- Pita, G., Gielen, B., Zona, D., Rodrigues, A., Rambal, S., Janssens, I. A. and Ceulemans, R., Carbon and water vapor fluxes over four forests in two contrasting climatic zones. Agric. For. Meteorol., 2013, 180, 211–224.
- Carrara, A., Janssens, I. A., Yuste, J. C. and Ceulemans, R., Seasonal changes in photosynthesis, respiration and NEE of a mixed temperate forest. Agric. For. Meteorol., 2004, 126, 15–31.
- Valentini, R. et al., Respiration as the main determinant of carbon balance in European forests. Nature, 2000, 404, 861–865.
- Giardina, C. P. and Ryan, M. G., Evidence that decomposition rates of organic carbon in mineral soil do not vary with temperature. Nature, 2000, 404, 858–861.
- Krishna, M. P. and Mohan, M., Litter decomposition in forest ecosystems: a review. Energ. Ecol. Environ., 2017, 2, 236–249.
- Mahanta, R., Sarma, D. and Choudhury, A., Heavy rainfall occurrences in northeast India. Int. J. Climatol., 2013, 33, 1456–1469.
- Sarma, D., Baruah, K. K., Baruah, R., Gogoi, N., Bora, A., Chakraborty, S. and Karipot, A., Carbon dioxide, water vapour and energy fluxes over a semi-evergreen forest in Assam, Northeast India. J. Earth Syst. Sci., 2018, 127(7).
- Deb Burman, P. K., Sarma, D., Williams, M., Karipot, A. and Chakraborty, S., Estimating gross primary productivity of a tropical forest ecosystem over north-east India using LAI and meteorological variables. J. Earth Syst. Sci., 2017, 126.
- Rodda, S. R., Thumaty, K. C., Jha, C. S. and Dadhwal, V. K., Seasonal variations of carbondioxide, water vapor and energy fluxes in tropical Indian mangroves. Forests, 2016, 7(35).
- Lasslop, G. et al., Separation of net ecosystem exchange into assimilation and respiration using a light response curve approach: critical issues and global evaluation. Global Change Biol., 2010, 16, 187–208.
- Falge, E. et al., Gap filling strategies for defensible annual sums of net ecosystem exchange. Agric. For. Meteorol., 2001, 107, 43–69.
- Lloyd, J. and Taylor, J. A., On the temperature dependence of soil respiration. Funct. Ecol., 1994, 8(3), 315–323.
- Reichstein, M. et al., On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm. Global Change Biol., 2005, 11, 1424–1439.
- Korner, C., Leaf diffusive conductances in the major vegetation types of the globe. In Ecophysiology of Photosynthesis (eds Schulze, E. D. and Caldwell, M. M.), Springer, Berlin, 1995, pp. 463–490.
- Thomas, M. V. et al., Carbondioxide fluxes over an ancient broadleaved deciduous woodland in southern England. Biogeosciences, 2011, 8, 1595–1613.
- Heinemeyer, A., Hartley, I. P., Evans, S. P., Fuente, J. A. and Ineson, P., Forest soil CO2 flux: uncovering the contribution and environmental responses of ectomycorrhizas. Global Change Biol., 2007, 13, 1786–1797.
- Veenendaal, E., Kolle, O. and Lloyd, J., Seasonal variation in energy fluxes and carbondioxide exchange for a broad-leaved semi-arid savanna (Mopane woodland) in Southern Africa. Global Change Biol., 2004, 10, 318–328.
- Pandey, R. R., Sharma, G., Singh, T. B. and Tripathi, S. K., Factors influencing soil CO2 efflux in a northeastern Indian oak forest and plantation. Afr. J. Plant Sci., 2010, 4, 280–289.
- Sheikh, M. A., Kumar, M. and Bussmann, R. W., Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya. Carbon Balance Manage., 2009, 4(6).
- Potential of Reef Building Corals to Study the Past Indian Monsoon Rainfall Variability
Abstract Views :221 |
PDF Views:73
Authors
Affiliations
1 Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune 411 008, IN
1 Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune 411 008, IN
Source
Current Science, Vol 119, No 2 (2020), Pagination: 273-281Abstract
Reef building corals are known to provide high resolution records of ocean–atmospheric variables for the last several centuries. The most important parameter is the sea surface temperature, which is accurately recorded by the oxygen isotopic composition as well as by a few trace elemental ratios such as, Sr/Ca, Mg/Ca, U/Ca, etc. Determination of the sea surface temperature has enabled the palaeocenographers to study a variety of oceanic processes, such as the El Niño and Southern Oscillation, ocean circulation, air–sea gas exchange, Indian Ocean dipole, etc. Monsoon is an important atmospheric process in which sea surface temperature plays an active role in governing the moisture production and modulation of the wind circulation. Apart from temperature reconstruction, the corals have also been used to study the monsoon processes by some investigators, viz. the estimation of rainfall. In this article, we review the available coral records, specifically for studying the Indian summer monsoon rainfall variability. The study reveals that the coral records only from a few specific regions show promise in this endeavour.Keywords
Arabian Sea, coral, ISM, Lakshadweep, SST, δ18O.Full Text