@article{aneja_blunden_james_schlesinger_knighton_gilliam_jennings_niyogi_cole_2008, title={Ammonia assessment from agriculture: US status and needs}, volume={37}, ISSN={["1537-2537"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-40849136515&partnerID=MN8TOARS}, DOI={10.2134/jeq2007.0002in}, abstractNote={Abstract}, number={2}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Aneja, Viney P. and Blunden, Jessica and James, Kristen and Schlesinger, William H. and Knighton, Raymond and Gilliam, Wendell and Jennings, Greg and Niyogi, Dev and Cole, Shawn}, year={2008}, pages={515–520} }
 @article{occhipinti_aneja_showers_niyogi_2008, title={Back-trajectory analysis and source-receptor relationships: Particulate matter and nitrogen isotopic composition in rainwater}, volume={58}, ISSN={["1047-3289"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-53849144360&partnerID=MN8TOARS}, DOI={10.3155/1047-3289.58.9.1215}, abstractNote={Abstract The southeastern portion of North Carolina features a dense crop and animal agricultural region; previous research suggests that this agricultural presence emits a significant portion of the state’s nitrogen (i.e., oxides of nitrogen and ammonia) emissions. These findings indicate that transporting air over this region can affect nitrogen concentrations in precipitation at sites as far as 50 mi away. The study combined nitrate nitrogen isotope data with back-trajectory analysis to examine the relationship between regional nitrogen emission estimates independent of pollutant concentration information. In 2004, the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to determine potential sources of nitrogen in rainwater collected at an urban receptor site in Raleigh, NC. The δ15N isotope ratio signatures of each sample were used to further differentiate between sources of the rainwater nitrate. This study examined the importance of pollution sources, including animal agricultural activity, and meteorology on rainfall chemistry as well as the implications in fine particulate matter (PM2.5) formation. Samples that transited the dense crop and animal (swine) agricultural region of east-southeastern North Carolina (i.e., the source region) had lower δ15N isotope ratios in the nitrate ion (average = −2.1 ± 1.7‰) than those from a counterpart nonagricultural region (average = 0.1 ± 3‰.) An increase in PM2.5 concentrations in the urban receptor site (yearly average = 15.1 ± 5.8 μg/m3) was also found to correspond to air transport over the dense agricultural region relative to air that was not subjected to such transport (yearly average = 11.7 ± 5.8 μg/m3).}, number={9}, journal={JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION}, author={Occhipinti, Chris and Aneja, Viney P. and Showers, William and Niyogi, Dev}, year={2008}, month={Sep}, pages={1215–1222} }
 @article{alapaty_niyogi_chen_pyle_chandrasekar_seaman_2008, title={Development of the flux-adjusting surface data assimilation system for mesoscale models}, volume={47}, ISSN={["1558-8432"]}, DOI={10.1175/2008JAMC1831.1}, abstractNote={Abstract}, number={9}, journal={JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY}, author={Alapaty, Kiran and Niyogi, Dev and Chen, Fei and Pyle, Patrick and Chandrasekar, Anantharman and Seaman, Nelson}, year={2008}, month={Sep}, pages={2331–2350} }
 @article{aneja_blunden_roelle_schlesinger_knighton_niyogi_gilliam_jennings_duke_2008, title={Workshop on Agricultural Air Quality: State of the science}, volume={42}, ISSN={["1873-2844"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-41449102642&partnerID=MN8TOARS}, DOI={10.1016/j.atmosenv.2007.07.043}, abstractNote={The first Workshop on Agricultural Air Quality: State of the Science was held at the Bolger Center in Potomac, Maryland from 4 to 8 June 2006. This international conference assembled approximately 350 people representing 25 nations from 5 continents, with disciplines ranging from atmospheric chemistry to soil science. The workshop was designed as an open forum in which participants could openly exchange the most current knowledge and learn about numerous international perspectives regarding agricultural air quality. Participants represented many stakeholder groups concerned with the growing need to assess agricultural impacts on the atmosphere and to develop beneficial policies to improve air quality. The workshop focused on identifying methods to improve emissions inventories and best management practices for agriculture. Workshop participants also made recommendations for technological and methodological improvements in current emissions measurement and modeling practices. The workshop commenced with a session on agricultural emissions and was followed by international perspectives from the United States, Europe, Australia, India, and South America. This paper summarizes the findings and issues of the workshop and articulates future research needs. These needs were identified in three general areas: (1) improvement of emissions measurement; (2) development of appropriate emission factors; and (3) implementation of best management practices (BMPs) to minimize negative environmental impacts. Improvements in the appropriate measurements will inform decisions regarding US farming practices. A need was demonstrated for a national/international network to monitor atmospheric emissions from agriculture and their subsequent depositions to surrounding areas. Information collected through such a program may be used to assess model performance and could be critical for evaluating any future regulatory policies or BMPs. The workshop concluded that efforts to maximize benefits and reduce detrimental effects of agricultural production need to transcend disciplinary, geographic, and political boundaries. Also, such efforts should involve natural and social scientists, economists, engineers, business leaders, and decision makers. The workshop came to the conclusion that through these collaborative efforts improvements in air quality from agricultural practices will begin to take effect.}, number={14}, journal={ATMOSPHERIC ENVIRONMENT}, author={Aneja, Viney P. and Blunden, Jessica and Roelle, Paul A. and Schlesinger, William H. and Knighton, Raymond and Niyogi, Dev and Gilliam, Wendell and Jennings, Greg and Duke, Clifford S.}, year={2008}, month={Apr}, pages={3195–3208} }
 @article{aneja_niyogi_roelle_2006, title={An integrated perspective on assessing agricultural air quality}, volume={6}, ISBN={1466-6650}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-33746227332&partnerID=MN8TOARS}, DOI={10.1504/ijgenvi.2006.010146}, abstractNote={The biogeochemical cycling of trace gases (e.g. nitrogen, sulphur, etc.), and contaminants on local, regional, and global scales is a complex system of emissions, transformations, transport, and deposition. To date, limited, if any, attempt has been made on quantifying and identifying direct emissions of gaseous sulphur compounds from agricultural operations. This represents a major regulatory need for sound and prudent environmental practice. In this paper, we summarise an integrated assessment framework for studying the agricultural air quality issues by discussing the various components of the research, education and outreach involved.}, number={2-3}, journal={International Journal of Global Environmental Issues}, author={Aneja, Viney and Niyogi, D. and Roelle, P.A.}, year={2006}, pages={137–148} }
 @article{fall_niyogi_semazzi_2006, title={Analysis of mean climate conditions in Senegal (1971-98)}, volume={10}, DOI={10.1175/ei158.1}, abstractNote={Abstract}, journal={Earth Interactions}, author={Fall, S. and Niyogi, D. and Semazzi, F. H. M.}, year={2006} }
 @article{holder_boyles_syed_niyogi_raman_2006, title={Comparison of collocated automated (NCECONet) and manual (COOP) climate observations in North Carolina}, volume={23}, ISSN={["0739-0572"]}, DOI={10.1175/jtech1873.1}, abstractNote={Abstract}, number={5}, journal={JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY}, author={Holder, C and Boyles, R and Syed, A and Niyogi, D and Raman, S}, year={2006}, month={May}, pages={671–682} }
 @article{alpert_niyogi_pielke_eastman_xue_raman_2006, title={Evidence for carbon dioxide and moisture interactions from the leaf cell up to global scales: Perspective on human-caused climate change}, volume={54}, ISSN={["1872-6364"]}, DOI={10.1016/j.gloplacha.2006.03.015}, abstractNote={It is of utmost interest to further understand the mechanisms behind the potential interactions or synergies between the greenhouse gases (GHG) forcing(s), particularly as represented by CO2, and water processes and through different climatic scales down to the leaf scale. Toward this goal, the factor separation methodology introduced by Stein and Alpert [Stein U. and Alpert, P. 1993. Factor separation in numerical simulations, J. Atmos. Sci., 50, 2107–2115.] that allows an explicit separation of atmospheric synergies among different factors, is employed. Three independent experiments carried out recently by the present authors, are reported here, all strongly suggest the existence of a significant CO2–water synergy in all the involved scales. The experiments employed a very wide range of up-to-date atmospheric models that complement the physics currently introduced in most Global Circulation Models (GCMs) for global climate change prediction. Threemodelingexperimentsthatgofromthesmall/microscale(leafscaleandsoilmoisture) tomesoscale(land-usechangeandCO2 effects ) andtoglobalscale (greenhousegasesand cloudiness)all showthatsynergies between water and CO2are essential inpredicting carbonassimilation,minimumdailytemperatureandtheglobalEarthtemperature,respectively.Thestudyalsohighlightstheimportance of including the physics associated with carbon–water synergy which is mostly unresolved in global climate models suggesting that significantcarbon–waterinteractionsarenotincorporatedoratleastwellparameterizedincurrentclimatemodels.Hence,thereisaneed for integrative climate models. As shown in earlier studies, the climate involves physical, chemical and biological processes. To only include a subset of these processes limits the skill of local, regional and global models to simulate the real climate system. In addition, our results provide explicit determination of the direct and the interactive effect of the CO2 response on the terrestrial biosphere response. There is also an implicit scale interactive effect that can be deduced from the multiscale effects discussed in the three examples.Processesateachscale-leaf,regionalandglobalwillallsynergisticallycontributetoincreasethefeedbacks —whichcandecrease or increase the overall system's uncertainty depending on specific case/setup and needs to beexamined in futurecoupled, multiscalestudies.}, number={1-2}, journal={GLOBAL AND PLANETARY CHANGE}, author={Alpert, P. and Niyogi, D. and Pielke, R. A., Sr. and Eastman, J. L. and Xue, Y. K. and Raman, S.}, year={2006}, month={Nov}, pages={202–208} }
 @article{mera_niyogi_buol_wilkerson_semazzi_2006, title={Potential individual versus simultaneous climate change effects on soybean (C-3) and maize (C-4) crops: An agrotechnology model based study}, volume={54}, ISSN={["1872-6364"]}, DOI={10.1016/j.gloplacha.2005.11.003}, abstractNote={Landuse/landcover change induced effects on regional weather and climate patterns and the associated plant response or agricultural productivity are coupled processes. Some of the basic responses to climate change can be detected via changes in radiation (R), precipitation (P), and temperature (T). Past studies indicate that each of these three variables can affect LCLUC response and the agricultural productivity. This study seeks to address the following question: What is the effect of individual versus simultaneous changes in R, P, and T on plant response such as crop yields in a C3 and a C4 plant? This question is addressed by conducting model experiments for soybean (C3) and maize (C4) crops using the DSSAT: Decision Support System for Agrotechnology Transfer, CROPGRO (soybean), and CERES-Maize (maize) models. These models were configured over an agricultural experiment station in Clayton, NC [35.65°N, 78.5°W]. Observed weather and field conditions corresponding to 1998 were used as the control. In the first set of experiments, the CROPGRO (soybean) and CERES-Maize (maize) responses to individual changes in R and P (25%, 50%, 75%, 150%) and T (± 1, ± 2 °C) with respect to control were studied. In the second set, R, P, and T were simultaneously changed by 50%, 150%, and ± 2 °C, and the interactions and direct effects of individual versus simultaneous variable changes were analyzed. For the model setting and the prescribed environmental changes, results from the first set of experiments indicate: (i) precipitation changes were most sensitive and directly affected yield and water loss due to evapotranspiration; (ii) radiation changes had a non-linear effect and were not as prominent as precipitation changes; (iii) temperature had a limited impact and the response was non-linear; (iv) soybeans and maize responded differently for R, P, and T, with maize being more sensitive. The results from the second set of experiments indicate that simultaneous change analyses do not necessarily agree with those from individual changes, particularly for temperature changes. Our analysis indicates that for the changing climate, precipitation (hydrological), temperature, and radiative feedbacks show a non-linear effect on yield. Study results also indicate that for studying the feedback between the land surface and the atmospheric changes, (i) there is a need for performing simultaneous parameter changes in the response assessment of cropping patterns and crop yield based on ensembles of projected climate change, and (ii) C3 crops are generally considered more sensitive than C4; however, the temperature–radiation related changes shown in this study also effected significant changes in C4 crops. Future studies assessing LCLUC impacts, including those from agricultural cropping patterns and other LCULC–climate couplings, should advance beyond the sensitivity mode and consider multivariable, ensemble approaches to identify the vulnerability and feedbacks in estimating climate-related impacts.}, number={1-2}, journal={GLOBAL AND PLANETARY CHANGE}, author={Mera, Roberto J. and Niyogi, Dev and Buol, Gregory S. and Wilkerson, Gail G. and Semazzi, Fredrick H. M.}, year={2006}, month={Nov}, pages={163–182} }
 @article{fall_semazzi_dutta_niyogi_anyah_bowden_2006, title={The spatiotemporal climate variability over Senegal and its relationship to global climate}, volume={26}, ISSN={["1097-0088"]}, url={http://dx.doi.org/10.1002/joc.1355}, DOI={10.1002/joc.1355}, abstractNote={Abstract}, number={14}, journal={INTERNATIONAL JOURNAL OF CLIMATOLOGY}, author={Fall, Souleymane and Semazzi, Fredrick H. M. and Dutta, Dev and Niyogi, S. and Anyah, Richard O. and Bowden, Jared}, year={2006}, month={Nov}, pages={2057–2076} }
 @article{niyogi_chang_saxena_holt_alapaty_booker_chen_davis_holben_matsui_et al._2004, title={Direct observations of the effects of aerosol loading on net ecosystem CO2 exchanges over different landscapes}, volume={31}, ISSN={["0094-8276"]}, DOI={10.1029/2004gl020915}, abstractNote={We present the first direct, multisite observations in support of the hypothesis that atmospheric aerosols affect the regional terrestrial carbon cycle. The daytime growing season (summer) CO2 flux observations from six sites (forest, grasslands, and croplands) with collocated aerosol and surface radiation measurements were analyzed for high and low diffuse radiation; effect of cloud cover; and effect of high and low aerosol optical depths (AOD). Results indicate that, aerosols exert a significant impact on net CO2 exchange, and their effect may be even more significant than that due to clouds. The response appears to be a general feature irrespective of the landscape and photosynthetic pathway. The CO2 sink increased with aerosol loading for forest and crop lands, and decreased for grassland. The cause for the difference in response between vegetation types is hypothesized to be canopy architecture.}, number={20}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Niyogi, D and Chang, HI and Saxena, VK and Holt, T and Alapaty, K and Booker, F and Chen, F and Davis, KJ and Holben, B and Matsui, T and et al.}, year={2004}, month={Oct} }
 @article{gilliam_raman_niyogi_2004, title={Observational and numerical study on the influence of large-scale flow direction and coastline shape on sea-breeze evolution}, volume={111}, ISSN={["1573-1472"]}, DOI={10.1023/B:BOUN.0000016494.99539.5a}, number={2}, journal={BOUNDARY-LAYER METEOROLOGY}, author={Gilliam, RC and Raman, S and Niyogi, DDS}, year={2004}, month={May}, pages={275–300} }
 @article{matsui_kreidenweis_pielke_schichtel_yu_chin_chu_niyogi_2004, title={Regional comparison and assimilation of GOCART and MODIS aerosol optical depth across the eastern US}, volume={31}, number={21}, journal={Geophysical Research Letters}, author={Matsui, T. and Kreidenweis, S. M. and Pielke, R. A. and Schichtel, B. and Yu, H. B. and Chin, M. and Chu, D. A. and Niyogi, D.}, year={2004} }
 @article{yadav_raman_niyogi_2003, title={A note on the estimation of eddy diffusivity and dissipation length in low winds over a tropical urban terrain}, volume={160}, ISSN={["0033-4553"]}, DOI={10.1007/s00024-003-8785-4}, number={1-2}, journal={PURE AND APPLIED GEOPHYSICS}, author={Yadav, AK and Raman, S and Niyogi, DDS}, year={2003}, month={Jan}, pages={395–404} }
 @article{niyogi_alapaty_raman_2003, title={A photosynthesis-based dry deposition modeling approach}, volume={144}, ISSN={["1573-2932"]}, DOI={10.1023/A:1022955220354}, number={1}, journal={WATER AIR AND SOIL POLLUTION}, author={Niyogi, DDS and Alapaty, K and Raman, S}, year={2003}, pages={171–194} }
 @article{rhome_niyogi_raman_2003, title={Assessing seasonal transport and deposition of agricultural emissions in eastern North Carolina, USA}, volume={160}, ISSN={["0033-4553"]}, DOI={10.1007/s00024-003-8769-4}, number={1-2}, journal={PURE AND APPLIED GEOPHYSICS}, author={Rhome, JR and Niyogi, DDS and Raman, S}, year={2003}, month={Jan}, pages={117–141} }
 @article{marland_pielke_apps_avissar_betts_davis_frumhoff_jackson_joyce_kauppi_et al._2003, title={The climatic impacts of land surface change and carbon management, and the implications for climate-change mitigation policy}, volume={3}, ISSN={["1752-7457"]}, DOI={10.1016/S1469-3062(03)00028-7}, abstractNote={Strategies to mitigate anthropogenic climate change recognize that carbon sequestration in the terrestrial biosphere can reduce the build-up of carbon dioxide in the Earth’s atmosphere. However, climate mitigation policies do not generally incorporate the effects of these changes in the land surface on the surface albedo, the fluxes of sensible and latent heat to the atmosphere, and the distribution of energy within the climate system. Changes in these components of the surface energy budget can affect the local, regional, and global climate. Given the goal of mitigating climate change, it is important to consider all of the effects of changes in terrestrial vegetation and to work toward a better understanding of the full climate system. Acknowledging the importance of land surface change as a component of climate change makes it more challenging to create a system of credits and debits wherein emission or sequestration of carbon in the biosphere is equated with emission of carbon from fossil fuels. Recognition of the complexity of human-caused changes in climate does not, however, weaken the importance of actions that would seek to minimize our disturbance of the Earth’s environmental system and that would reduce societal and ecological vulnerability to environmental change and variability.}, number={2}, journal={CLIMATE POLICY}, author={Marland, G and Pielke, RA and Apps, M and Avissar, R and Betts, RA and Davis, KJ and Frumhoff, PC and Jackson, ST and Joyce, LA and Kauppi, P and et al.}, year={2003}, month={Jun}, pages={149–157} }
 @article{sims_niyogi_raman_2002, title={Adopting drought indices for estimating soil moisture: A North Carolina case study}, volume={29}, ISSN={["0094-8276"]}, DOI={10.1029/2001gl013343}, abstractNote={Soil moisture availability has a significant impact on environmental processes of different scales. Errors in initializing soil moisture in numerical weather forecasting models tend to cause errors in short‐term weather and medium range predictions. We study the use of two drought indices: Palmer Drought Severity Index (PDSI) values and Standardized Precipitation Index (SPI) for estimating soil moisture. SPI and PDSI values are compared for three climate divisions: western mountains, central piedmont, and the coastal plain in North Carolina, USA. Results suggest SPI to be more representative of short‐term precipitation and soil moisture variation and hence a better indicator of soil wetness. A regression equation that uses SPI is proposed to estimate soil moisture.}, number={8}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Sims, AP and Niyogi, DDS and Raman, S}, year={2002}, month={Apr} }
 @article{raman_niyogi_simpson_pelon_2002, title={Dynamics of the elevated land plume over the Arabian Sea and the Northern Indian Ocean during northeasterly monsoons and during the Indian Ocean experiment (INDOEX)}, volume={29}, ISSN={["0094-8276"]}, DOI={10.1029/2001gl014193}, abstractNote={We describe the dynamics of the formation of an elevated land plume over the Arabian Sea and northern Indian Ocean observed during the 1999 Indian Ocean Experiment (INDOEX). The presence of the elevated plume above the marine boundary layer for a depth of about 2000 m could be inferred from the thermodynamic profiles of the lower troposphere obtained from research vessels in 1997, 1998, and 1999, and in the lidar data obtained from aircraft during the INDOEX. Formation of the elevated plume was investigated further using a three‐dimensional high‐resolution mesoscale modeling system. The plume extends for hundreds of kilometers and its strength and coherence is influenced by the diurnal variation of the upwind continental boundary layer.}, number={16}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Raman, S and Niyogi, DDS and Simpson, M and Pelon, J}, year={2002}, month={Aug} }
 @article{niyogi_xue_raman_2002, title={Hydrological land surface response in a tropical regime and a midlatitudinal regime}, volume={3}, ISSN={["1525-755X"]}, DOI={10.1175/1525-7541(2002)003<0039:HLSRIA>2.0.CO;2}, abstractNote={A statistical‐dynamical study was performed on the role of hydrometeorological interactions in the midlatitudes and the semiarid Tropics. For this, observations from two field experiments, the First International Satellite Land Surface Climatology Project Field Experiment (FIFE) and the Hydrological Atmospheric Pilot Experiment (HAPEX)‐Sahel, representative of the midlatitudes and the semiarid tropical conditions, and simulated results from a land surface model, Simplified Simple Biosphere (SSiB) model were statistically analyzed for direct and interaction effects. The study objectives were to test the hypothesis that there are significant differences in the land surface processes in the semiarid tropical and midlatitudinal regimes and to identify the nature of the differences in the evapotranspiration exchanges for the two biogeographical domains. Results suggest there are similarities in the direct responses but the interactions or the indirect feedback pathways could be very different. The arid tropical regimes are dominated through vegetative pathways (via variables such leaf area index, stomatal resistance, and vegetal cover); the midlatitudes show soil wetness (moisture)‐related feedback. In addition, for the midlatitudinal case, the vegetation and the soil surface acted in unison, leading to more interactive exchanges between the vegetation and the soil surface. The water-stressed semiarid tropical surface, on the other hand, showed response either directly between the vegetation and the atmosphere or between the soil and the atmosphere with very little interaction between the vegetation and the soil variables. Thus, the semiarid Tropics would require explicit bare ground and vegetation fluxes consideration, whereas the effective (combined vegetation and soil fluxes) surface representation used in various models may be more valid for the midlatitudinal case. This result also implied that with higher resource (water) availability the surface invested more in the surrounding environment. On the other hand, with poor resource availability (such as water stress in the tropical site), the surface components retain individual resources without sharing.}, number={1}, journal={JOURNAL OF HYDROMETEOROLOGY}, author={Niyogi, DDS and Xue, YK and Raman, S}, year={2002}, pages={39–56} }
 @article{pielke_marland_betts_chase_eastman_niles_niyogi_running_2002, title={The influence of land-use change and landscape dynamics on the climate system: relevance to climate-change policy beyond the radiative effect of greenhouse gases}, volume={360}, ISSN={["1364-503X"]}, DOI={10.1098/rsta.2002.1027}, abstractNote={Our paper documents that land-use change impacts regional and global climate through the surface-energy budget, as well as through the carbon cycle. The surface-energy budget effects may be more important than the carbon-cycle effects. However, land-use impacts on climate cannot be adequately quantified with the usual metric of ‘global warming potential’. A new metric is needed to quantify the human disturbance of the Earth's surface-energy budget. This ‘regional climate change potential’ could offer a new metric for developing a more inclusive climate protocol. This concept would also implicitly provide a mechanism to monitor potential local-scale environmental changes that could influence biodiversity.}, number={1797}, journal={PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES}, author={Pielke, RA and Marland, G and Betts, RA and Chase, TN and Eastman, JL and Niles, JO and Niyogi, DDS and Running, SW}, year={2002}, month={Aug}, pages={1705–1719} }
 @article{satyanarayana_mohanty_niyogi_raman_lykossov_warrior_sam_2001, title={A study on marine boundary layer processes in the ITCZ and non-ITCZ regimes over Indian Ocean with INDOEX IFP-99 data}, volume={80}, number={2001 Apr. 10}, journal={Current Science}, author={Satyanarayana, A. N. V. and Mohanty, U. C. and Niyogi, D. S. and Raman, S. and Lykossov, V. N. and Warrior, H. and Sam, N. V.}, year={2001}, pages={39–45} }
 @article{roswintiarti_raman_mohanty_niyogi_2001, title={A study on the performance of a triple nested mesoscale model over tropical Indian Ocean during INDOEX}, volume={80}, number={2001 Apr. 10}, journal={Current Science}, author={Roswintiarti, O. and Raman, S. and Mohanty, U. C. and Niyogi, D. S.}, year={2001}, pages={77–84} }
 @article{roswintiarti_raman_mohanty_niyogi_2001, title={Application of three-dimensional triple nested mesoscale model for assessing the transport and boundary layer variability over the Indian Ocean during INDOEX}, volume={80}, number={2001 Apr. 10}, journal={Current Science}, author={Roswintiarti, O. and Raman, S. and Mohanty, U. C. and Niyogi, D. S.}, year={2001}, pages={69–76} }
 @article{alapaty_seaman_niyogi_hanna_2001, title={Assimilating surface data to improve the accuracy of atmospheric boundary layer simulations}, volume={40}, ISSN={["0894-8763"]}, DOI={10.1175/1520-0450(2001)040<2068:ASDTIT>2.0.CO;2}, abstractNote={Large errors in atmospheric boundary layer (ABL) simulations can be caused by inaccuracies in the specification of surface characteristics in addition to assumptions and simplifications made in boundary layer formulations or other model deficiencies. For certain applications, such as air quality studies, these errors can have significant effects. To reduce such errors, a continuous surface data assimilation technique is developed. In this technique, surface-layer temperature and water vapor mixing ratio are directly assimilated by using the analyzed surface data. Then, the difference between the observations and model results is used to calculate adjustments to the surface fluxes of sensible and latent heat. These adjustments are then used to calculate a new estimate of the ground temperature, thereby affecting the simulated surface fluxes on the subsequent time step. This indirect data assimilation is applied simultaneously with the direct assimilation of surface data in the model’s lowest layer, thereby maintaining greater consistency between the ground temperature and the surface-layer mass-field variables. A one-dimensional model was used to study the improvements that result from applying this technique for ABL simulations in two cases. It was found that application of the new technique led to significant reductions in ABL modeling errors.}, number={11}, journal={JOURNAL OF APPLIED METEOROLOGY}, author={Alapaty, K and Seaman, NL and Niyogi, DS and Hanna, AF}, year={2001}, pages={2068–2082} }
 @article{mohanty_niyogi_raman_sarkar_2001, title={Numerical study of the role of land-air-sea interactions for the northeasterly monsoon circulations over Indian Ocean during INDOEX}, volume={80}, number={2001 Apr. 10}, journal={Current Science}, author={Mohanty, U. C. and Niyogi, D. S. and Raman, S. and Sarkar, A.}, year={2001}, pages={60–68} }
 @article{manghnani_raman_niyogi_parameswara_morrison_ramana_raju_2000, title={Marine boundary-layer variability over the Indian Ocean during INDOEX (1998)}, volume={97}, ISSN={["0006-8314"]}, DOI={10.1023/A:1002730405170}, number={3}, journal={BOUNDARY-LAYER METEOROLOGY}, author={Manghnani, V and Raman, S and Niyogi, DS and Parameswara, V and Morrison, JM and Ramana, SV and Raju, JVSS}, year={2000}, month={Dec}, pages={411–430} }
 @article{rhome_niyogi_raman_2000, title={Mesoclimatic analysis of severe weather and ENSO interactions in North Carolina}, volume={27}, ISSN={["0094-8276"]}, DOI={10.1029/1999GL011327}, abstractNote={Connections between regional severe weather occurrences and El Niño/Southern Oscillation (ENSO) are investigated. Monthly (1950 –1989) occurrences of tornado and wind/hail frequency are compared with sea surface temperature (SST) indices and anomalies in the tropical Pacific. Analyses indicate increase in wind/hail events/ days, during the months of April through June of La Niña years. No direct evidence is found between tornado frequency and ENSO classes. Using seasonal composite anomalies of upper‐air patterns, it is concluded that La Niña patterns leads to enhanced convection over North Carolina.}, number={15}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Rhome, JR and Niyogi, DS and Raman, S}, year={2000}, month={Aug}, pages={2269–2272} }
 @article{niyogi_raman_alapaty_1999, title={Uncertainty in the specification of surface characteristics, part II: Hierarchy of interaction-explicit statistical analysis}, volume={91}, DOI={10.1023/A:1002023724201}, number={3}, journal={Boundary-layer Meteorology}, author={Niyogi, D. S. and Raman, S. and Alapaty, K.}, year={1999}, pages={341–366} }
 @article{niyogi_raman_alapaty_1998, title={Comparison of four different stomatal resistance schemes using FIFE data. Part II: Analysis of terrestrial biospheric-atmospheric interactions}, volume={37}, ISSN={["0894-8763"]}, DOI={10.1175/1520-0450(1998)037<1301:COFDSR>2.0.CO;2}, abstractNote={Stomatal resistance (Rs) forms a pivotal component of the surface energy budget and of the terrestrial biosphere‐atmosphere interactions. Using a statistical‐graphical technique, the Rs-related interactions between different atmospheric and physiological variables are resolved explicitly from observations made during the First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE). A similar analysis was undertaken for the Rs parameterization schemes, as used in the present models. Three physiological schemes (the Ball‐Woodrow‐Berry, Kim and Verma, and Jacobs) and one operational Jarvis-type scheme were evaluated in terms of their ability to replicate the terrestrial biosphere‐atmosphere interactions. It was found that all of the Rs parameterization schemes have similar qualitative behavior for routine meteorological applications (without carbon assimilation). Compared to the observations, there was no significant difference found in employing either the relative humidity or the vapor pressure deficit as the humidity descriptor in the analysis. Overall, the relative humidity‐based interactions were more linear than the vapor pressure deficit and hence could be considered more convenient in the scaling exercises. It was found that with high photosynthesis rates, all of the schemes had similar behavior. It was found with low assimilation rates, however, that the discrepancies and nonlinearity in the interactions, as well as the uncertainties, were exaggerated.}, number={10}, journal={JOURNAL OF APPLIED METEOROLOGY}, author={Niyogi, DS and Raman, S and Alapaty, K}, year={1998}, month={Oct}, pages={1301–1320} }
 @article{raman_reddy_niyogi_1998, title={Mesoscale analysis of a Carolina coastal front}, volume={86}, ISSN={["0006-8314"]}, DOI={10.1023/A:1000605030775}, number={1}, journal={BOUNDARY-LAYER METEOROLOGY}, author={Raman, S and Reddy, NC and Niyogi, DS}, year={1998}, month={Jan}, pages={125–145} }
 @article{raman_niyogi_prabhu_ameenullah_nagaraj_kumar_jayanna_1998, title={TVEBEX: Vegetation and surface energy balance experiment for the tropics}, volume={107}, DOI={10.1007/bf02842263}, abstractNote={Surface features such as soil moisture and vegetation have a profound impact on the surface energy balance and the atmospheric boundary layer. To quantify this effect for a tropical location, a detailed field experiment, VEBEX, was designed and successfully executed in a tropical site at Bangalore, India. VEBEX was a joint experiment between the North Carolina State University, Indian Institute of Science (IISc), and the University of Agricultural Science (UAS) at Bangalore, India. Continuous surface meteorological measurements were taken over an entire crop period (pre-sowing to post-harvest). During different stages of the plant growth, intensive observations of surface turbulence, and measurements of physiological and soil moisture measurements were also conducted. The results obtained provide an insight into the unusually strong variability for the tropics. Interpretation of the observations and an overview of the analysis procedure and future research initiatives are also presented.}, number={1}, journal={Proceedings (Indian Academy of Sciences). Earth and Planetary Sciences}, author={Raman, Sethu and Niyogi, D. S. and Prabhu, A. and Ameenullah, S. and Nagaraj, S. T. and Kumar, U. and Jayanna, S.}, year={1998}, pages={97–105} }
 @article{roswintiarti_niyogi_raman_1998, title={Teleconnections between tropical Pacific sea surface temperature anomalies and North Carolina precipitation anomalies during El Nino events}, volume={25}, ISSN={["0094-8276"]}, DOI={10.1029/1998GL900121}, abstractNote={Linear teleconnections of El Niño events and precipitation over a regional coastal land mass were analyzed. Two statistical techniques were used. First, the Empirical Orthogonal Function extracted major variances of the monthly tropical Pacific sea surface temperature anomalies and coastal North Carolina precipitation anomalies. Second, the Canonical Correlation Analysis calculated the linear combinations of the anomaly data sets that were highly correlated. The results show that El Niño‐related precipitation anomalies along the North Carolina coast were positive from November to May and negative between June and October consistent with large‐scale studies. Results indicate simple, linear statistical techniques can be effectively adopted to determine teleconnections on a local scale.}, number={22}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Roswintiarti, O and Niyogi, DS and Raman, S}, year={1998}, month={Nov}, pages={4201–4204} }
 @article{niyogi_raman_1997, title={Comparison of four different stomatal resistance schemes using FIFE observations}, volume={36}, ISSN={["0894-8763"]}, DOI={10.1175/1520-0450(1997)036<0903:COFDSR>2.0.CO;2}, abstractNote={Stomatal resistance (Rs) calculation has a major impact on the surface energy partitioning that influences diverse boundary layer processes. Present operational limited area or mesoscale models have the Jarvis-type parameterization, whereas the microscale and the climate simulation models prefer physiological schemes for estimating Rs. The pivotal question regarding operational mesoscale models is whether an iterative physiological scheme needs to be adopted ahead of the analytical Jarvis-type formulation. This question is addressed by comparing the ability of three physiological schemes along with a typical Jarvistype scheme for predicting Rs using observations made during FIFE. The data used is typical of a C4-type vegetation, predominant in regions of high convective activity such as the semiarid Tropics and the southern United States grasslands. Data from three different intensive field campaigns are analyzed to account for vegetation and hydrological diversity. It is found that the Jarvis-type approach has low variance in the outcome due to a poor feedback for the ambient changes. The physiological models, on the other hand, are found to be quite responsive to the external environment. All three physiological schemes have a similar performance qualitatively, which suggests that the vapor pressure deficit approach or the relative humidity descriptor used in the physiological schemes may not yield different results for routine meteorological applications. For the data considered, the physiological schemes had a consistently better performance compared to the Jarvis-type scheme in predicting Rs outcome. All four schemes can, however, provide a reasonable estimate of the ensemble mean of the samples considered. A significant influence of the seasonal change in the minimum Rs in the Jarvis-type scheme was also noticed, which suggests the use of nitrogen-based information for improving the performance of the Jarvis-type scheme. A possible interactive influence of soil moisture on the capabilities of the four schemes is also discussed. Overall, the physiological schemes performed better under higher moisture availability.}, number={7}, journal={JOURNAL OF APPLIED METEOROLOGY}, author={Niyogi, DS and Raman, S}, year={1997}, month={Jul}, pages={903–917} }
 @article{niyogi_raman_prabhu_kumar_joshi_1997, title={Direct estimation of stomatal resistance for meteorological applications}, volume={24}, ISSN={["0094-8276"]}, DOI={10.1029/97GL01790}, abstractNote={Stomatal Resistance (Rs) is one of the most important parameters in the meteorological models for weather or climate analysis and hydrological scenario estimations. The information for estimating Rs is sparse particularly in the tropics limiting the development of a detailed global terrestrial biosphere‐atmosphere interaction analysis. One of the reasons for the scarcity of tropical data is the high cost of instrumentation. A hypothesis is presented to estimate Rs from plant‐nutrient status in a field study using stomatal aperture observations to develop a simple, cost‐effective technique for first‐order estimations. Comparisons with observations from a tropical field experiment are encouraging and an approach is suggested using this method for initialization of numerical models using remote sensing techniques based on nitrogen, humidity, and temperature as sufficient parameters.}, number={14}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Niyogi, DS and Raman, S and Prabhu, A and Kumar, U and Joshi, SS}, year={1997}, month={Jul}, pages={1771–1774} }
 @article{alapaty_raman_niyogi_1997, title={Uncertainty in the specification of surface characteristics: A study of prediction errors in the boundary layer}, volume={82}, ISSN={["0006-8314"]}, DOI={10.1023/A:1017166907476}, number={3}, journal={BOUNDARY-LAYER METEOROLOGY}, author={Alapaty, K and Raman, S and Niyogi, DS}, year={1997}, month={Mar}, pages={473–500} }