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617 results on '"Kalnay, Eugenia"'

215. Agricultural Green Revolution as a driver of increasing atmospheric CO2 seasonal amplitude.

Author

Zeng, Ning, Zhao, Fang, Kalnay, Eugenia, Salawitch, Ross J., Collatz, George J., West, Tristram O., and Guanter, Luis

Subjects
AGRICULTURAL technology, GREEN Revolution, ATMOSPHERIC carbon dioxide, AGRICULTURAL productivity, BIOSPHERE
Abstract

The atmospheric carbon dioxide (CO2) record displays a prominent seasonal cycle that arises mainly from changes in vegetation growth and the corresponding CO2 uptake during the boreal spring and summer growing seasons and CO2 release during the autumn and winter seasons. The CO2 seasonal amplitude has increased over the past five decades, suggesting an increase in Northern Hemisphere biospheric activity. It has been proposed that vegetation growth may have been stimulated by higher concentrations of CO2 as well as by warming in recent decades, but such mechanisms have been unable to explain the full range and magnitude of the observed increase in CO2 seasonal amplitude. Here we suggest that the intensification of agriculture (the Green Revolution, in which much greater crop yield per unit area was achieved by hybridization, irrigation and fertilization) during the past five decades is a driver of changes in the seasonal characteristics of the global carbon cycle. Our analysis of CO2 data and atmospheric inversions shows a robust 15 per cent long-term increase in CO2 seasonal amplitude from 1961 to 2010, punctuated by large decadal and interannual variations. Using a terrestrial carbon cycle model that takes into account high-yield cultivars, fertilizer use and irrigation, we find that the long-term increase in CO2 seasonal amplitude arises from two major regions: the mid-latitude cropland between 25° N and 60° N and the high-latitude natural vegetation between 50° N and 70° N. The long-term trend of seasonal amplitude increase is 0.311 ± 0.027 per cent per year, of which sensitivity experiments attribute 45, 29 and 26 per cent to land-use change, climate variability and change, and increased productivity due to CO2 fertilization, respectively. Vegetation growth was earlier by one to two weeks, as measured by the mid-point of vegetation carbon uptake, and took up 0.5 petagrams more carbon in July, the height of the growing season, during 2001-2010 than in 1961-1970, suggesting that human land use and management contribute to seasonal changes in the CO2 exchange between the biosphere and the atmosphere. [ABSTRACT FROM AUTHOR]

Published
2014
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216. AIRS

Author

CHAHINE, MOUSTAFA T., primary, PAGANO, THOMAS S., additional, AUMANN, HARTMUT H., additional, ATLAS, ROBERT, additional, BARNET, CHRISTOPHER, additional, BLAISDELL, JOHN, additional, CHEN, LUKE, additional, DIVAKARLA, MURTY, additional, FETZER, ERIC J., additional, GOLDBERG, MITCH, additional, GAUTIER, CATHERINE, additional, GRANGER, STEPHANIE, additional, HANNON, SCOTT, additional, IRION, FREDRICK W., additional, KAKAR, RAMESH, additional, KALNAY, EUGENIA, additional, LAMBRIGTSEN, BJORN H., additional, LEE, SUNG-YUNG, additional, Le MARSHALL, JOHN, additional, MCMILLAN, W. WALLACE, additional, MCMILLIN, LARRY, additional, OLSEN, EDWARD T., additional, REVERCOMB, HENRY, additional, ROSENKRANZ, PHILIP, additional, SMITH, WILLIAM L., additional, STAELIN, DAVID, additional, STROW, L. LARRABEE, additional, SUSSKIND, JOEL, additional, TOBIN, DAVID, additional, WOLF, WALTER, additional, and ZHOU, LIHANG, additional

Published
2006
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223. Climate (communication arising): Impact of land-use change on climate

Author

Cai, Ming and Kalnay, Eugenia

Subjects
Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Author(s): Ming Cai (corresponding author) [1]; Eugenia Kalnay [2] Cai and Kalnay reply We do not deny the obvious importance of global warming and decrease in diurnal temperature range (DTR) [...]

Published
2004
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228. The USWRP Workshop on the Weather Research Needs of the Private Sector

Author

Pielke, Roger A., primary, Abraham, Jim, additional, Abrams, Elliot, additional, Block, Jim, additional, Carbone, Richard, additional, Chang, David, additional, Droegemeier, Kelvin, additional, Emanuel, Kerry, additional, Friday, Elbert W(Joe), additional, Gall, Robert, additional, Gaynor, John, additional, Getz, Rodger R., additional, Glickman, Todd, additional, Hoggatt, Bradley, additional, Hooke, William H., additional, Johnson, Edward R., additional, Kalnay, Eugenia, additional, Kimpel, James(Jeff), additional, Kocin, Paul, additional, Marler, Byron, additional, Morss, Rebecca, additional, Nathan, Ravi, additional, Nelson, Steve, additional, Pielke, Roger, additional, Pirone, Maria, additional, Prater, Erwin, additional, Qualley, Warren, additional, Simmons, Kevin, additional, Smith, Michael, additional, Thomson, John, additional, and Wilson, Greg, additional

Published
2003
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234. Local Low Dimensionality and Relation to Effects Of Targeted Weather Observations.

Author

D.J.Patil, Szunyogh, Istvan, Zimin, Aleksey V, Hunt, Brian R., Ott, Edward, Kalnay, Eugenia, and Yorke, James A.

Subjects
WEATHER forecasting, STATISTICS, CHAOS theory, DIFFERENTIABLE dynamical systems
Abstract

A statistic, the BV (bred vector) dimension, is introduced to measure the effective local finite-time dimensionality of a spatiotemporally chaotic system. It is shown that the Earth’s atmosphere often has low BV-dimension. The implications for improving weather forecasting through data assimilation and targeted observations are discussed. © 2003 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2003
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236. The NCEP–NCAR 50–Year Reanalysis: Monthly Means CD–ROM and Documentation

Author

Kistler, Robert, primary, Collins, William, additional, Saha, Suranjana, additional, White, Glenn, additional, Woollen, John, additional, Kalnay, Eugenia, additional, Chelliah, Muthuvel, additional, Ebisuzaki, Wesley, additional, Kanamitsu, Masao, additional, Kousky, Vernon, additional, van den Dool, Huug, additional, Jenne, Roy, additional, and Fiorino, Michael, additional

Published
2001
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238. Bred vectors of the Lorenz63 system

Author

Zhang, Ying, Ide, Kayo, and Kalnay, Eugenia

Abstract

The breeding method has been widely used in studies of data assimilation, predictability and instabilities. The bred vectors (BVs), which are the nonlinear difference between the control and perturbed runs, represent the time-evolving rapidly growing errors in dynamic systems. The Lorenz (1963) model (hereafter Lorenz63 model) has chaotic dynamics similar to weather and climate. This study investigates the features of BVs of the Lorenz63 model and its impact on regime prediction of the Lorenz63 model. The results show that the Lorenz63 model has two different BVs for each breeding cycle, and the two BVs approach being identical when growth rate is high. The duration of the current and next regime is associated with the relative directions between the BV with high growth rate and the model trajectory.

Published
2015
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242. Ensemble transform Kalman-Bucy filters.

Author

Amezcua, Javier, Ide, Kayo, Kalnay, Eugenia, and Reich, Sebastian

Subjects
MATRIX inversion, STOCHASTIC processes, NUMERICAL analysis, PREDICTION theory, GENERALIZED inverses of linear operators
Abstract

Two recent works have adapted the Kalman-Bucy filter into an ensemble setting. In the first formulation, the ensemble of perturbations is updated by the solution of an ordinary differential equation (ODE) in pseudo-time, while the mean is updated as in the standard Kalman filter. In the second formulation, the full ensemble is updated in the analysis step as the solution of single set of ODEs in pseudo-time. Neither requires matrix inversions except for the frequently diagonal observation error covariance. We analyse the behaviour of the ODEs involved in these formulations. We demonstrate that they stiffen for large magnitudes of the ratio of background error to observational error variance, and that using the integration scheme proposed in both formulations can lead to failure. A numerical integration scheme that is both stable and is not computationally expensive is proposed. We develop transform-based alternatives for these Bucy-type approaches so that the integrations are computed in ensemble space where the variables are weights (of dimension equal to the ensemble size) rather than model variables. Finally, the performance of our ensemble transform Kalman-Bucy implementations is evaluated using three models: the 3-variable Lorenz 1963 model, the 40-variable Lorenz 1996 model, and a medium complexity atmospheric general circulation model known as SPEEDY. The results from all three models are encouraging and warrant further exploration of these assimilation techniques. [ABSTRACT FROM AUTHOR]

Published
2014
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243. Relative sea-level rise and the conterminous United States: Consequences of potential land inundation in terms of population at risk and GDP loss.

Author

Haer, Toon, Kalnay, Eugenia, Kearney, Michael, and Moll, Henk

Subjects
GEOGRAPHIC information systems, ABSOLUTE sea level change, GROSS domestic product, COMPUTER software, COASTS
Abstract

Highlights: [•] We analyse four relative sea-level rise scenarios for each US coastal state till 2100. [•] We calculate the consequence of sea-level rise on the aspects of land inundation, population at risk, and GDP loss using GIS software if no adaptive measures are taken. [•] We found that the estimated amount of land inundated is between 26,000 and 76,000km2 for the US coast in the year 2100. [•] We found that the estimated population at risk due to land inundation is between 1.8 and 7.4 million for the US coast in the year 2100. [•] We found that the estimated loss of GDP due to land inundation is between 70 and 289 billion USD/year for the US coast in the year 2100. [ABSTRACT FROM AUTHOR]

Published
2013
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247. Proceedings of the NMC/NESDIS/DOD Conference on DMSP Retrieval Products (1st), Held in Washington, DC on 14-15 April 1992

Author

PHILLIPS LAB HANSCOM AFB MA, Isaacs, Ronald G., Kalnay, Eugenia, Ohring, George, McClatchey, Robert A., PHILLIPS LAB HANSCOM AFB MA, Isaacs, Ronald G., Kalnay, Eugenia, Ohring, George, and McClatchey, Robert A.

Abstract

A collection of state-of-the-art papers on products from the Defense Meteorological Satellite Program (DMSP) sensors, particularly the SSM/T and SSM/I products are presented. Partial contents include: SM/I: Status Report; Calibration/Validation of the DMSP Microwave Water Vapor Sounder (SSM/T-2); Performance of DMSP Special Sensor Microwave Humidity Profiler (SSM/T-2) Preliminary Results; DMSP Block 6: A Data Driven Approach; NOAA/NESDIS: operational SSM/T Products and Distribution; NOAA/NESDIS SSM/T Algorithms and Evaluation; Defense Meteorological Satellite Program Microwave Radiometer Processing at Air Force Global Weather Central; DMSP Special Sensor Microwave/Imager Processing at the Fleet Numerical Oceanography Center: Operational Status, Application and Plans; An Overview of the Experimental SSM/I Orbit-by- Orbit Products System (SSMIPROD) at NOAA/NESDIS; SSM/I Mapped Experimental Environmental Image Products; SSM/I Total Precipitable Water Vapor Algorithms: A Reprise and Update; The Use of the DMSP SSM/I for the Generation of Precipitation Products at NOAA/NESDIS: Part 1: A Status Report; The Use of the DMSP SSM/I for the Generation of Precipitation Products at NOAA/NESDIS: Part 2: Scientific Results; Production and Evaluation of Experimental SSM/I Ice and Wind Products at NOAA/NESDIS; Real Time Quality Control of SSM/I Wind Speed Data; Status of NESDIS Distribution of SSM/I Products; Processing and Distributing SSM/I Data via the Wet Net Project.

Published
1992

249. Editorial

Author

Navon, Michael, primary, Kalnay, Eugenia, additional, and Stone, Peter, additional

Published
1998
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