- Expertise: numerical modeling of atmospheric and oceanic circulations for weather and climate prediction. ---------- ... moreExpertise: numerical modeling of atmospheric and oceanic circulations for weather and climate prediction. ---------- If you see my research interests described as "Space Plasma Physics United KingdomAgent Based Modeling and Simulation Agent-Based Computational EconomicsMagnetohydrodynamics", please ignore. Don't know who put it there. Haven't found a way to get rid of it.edit
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ABSTRACT Results from twin control simulations of CO2 gas exchange between the ocean and the atmosphere are presented here using the two NASA-GISS climate models, in which the same atmospheric component (modelE) is coupled to two... more
ABSTRACT Results from twin control simulations of CO2 gas exchange between the ocean and the atmosphere are presented here using the two NASA-GISS climate models, in which the same atmospheric component (modelE) is coupled to two different ocean models, the Russell ocean model and HYCOM. Both climate models are also coupled to the same ocean biogeochemistry module (NBOM) which estimates prognostic distributions for biotic and abiotic fields that influence the air-sea flux of CO2. The two coupled models are spun-up to equilibrium first without ocean biogeochemistry and then with it. The model differences are mainly attributed to the different ocean model and in particular vertical processes such as mixing and vertical advection. The surface flux is shown to depend crucially in surface wind differences as well as the distributions of pCO2 in the two models. HYCOM takes longer to reach equilibrium despite the fact that vertical mixing is lower and therefore should be bringing the mixed layer depth faster into equilibrium. The global meridional overturning circulation can explain much of the differences in the biological pump in the two models together with the differences in mixed layer depth which are responsible for different SST distributions in the two models and consequently different atmospheric feedbacks (in the wind, net heat and freshwater fluxes into the ocean).
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Research Interests: Geography and Climatology
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Lightning remains the most uncertain source of NOx. Most estimates of the global lightning NOx source have employed a bottom-up approach based on estimates of global flash rates and the number of molecules of NO produced per flash. We... more
Lightning remains the most uncertain source of NOx. Most estimates of the global lightning NOx source have employed a bottom-up approach based on estimates of global flash rates and the number of molecules of NO produced per flash. We interpret measurements of trace-gases from three satellite platforms to provide top-down constraints on the production of NO by lightning. The space
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Research Interests: Geography, Environmental Science, Climatology, Meteorology, Data Assimilation, and 12 moreNumerical Weather Prediction, Atmospheric sciences, Mesoscale Meteorology, High Resolution, Potential Vorticity, Terrain, Forecasting for Arima Model, Parameterization, Cartesian Coordinate System, Mesoscale, Vertical coordination, and Troposphere
The project objectives are to develop process models to investigate the interaction of planetary and synoptic-scale waves including the effects of latent heat release (precipitation), nonlinear dynamics, physical and boundary-layer... more
The project objectives are to develop process models to investigate the interaction of planetary and synoptic-scale waves including the effects of latent heat release (precipitation), nonlinear dynamics, physical and boundary-layer processes, and large-scale topography; to determine the importance of latent heat release for temporal variability and time-mean behavior of planetary and synoptic-scale waves; to compare the model results with available observations of planetary and synoptic wave variability; and to assess the implications of the results for monitoring precipitation in oceanic-storm tracks by satellite observing systems. Researchers have utilized two different models for this project: a two-level quasi-geostrophic model to study intraseasonal variability, anomalous circulations and the seasonal cycle, and a 10-level, multi-wave primitive equation model to validate the two-level Q-G model and examine effects of convection, surface processes, and spherical geometry. It explicitly resolves several planetary and synoptic waves and includes specific humidity (as a predicted variable), moist convection, and large-scale precipitation. In the past year researchers have concentrated on experiments with the multi-level primitive equation model. The dynamical part of that model is similar to the spectral model used by the National Meteorological Center for medium-range forecasts. The model includes parameterizations of large-scale condensation and moist convection. To test the validity of results regarding the influence of convective precipitation, researchers can use either one of two different convective schemes in the model, a Kuo convective scheme or a modified Arakawa-Schubert scheme which includes downdrafts. By choosing one or the other scheme, they can evaluate the impact of the convective parameterization on the circulation. In the past year researchers performed a variety of initial-value experiments with the primitive-equation model. Using initial conditions typical of climatological winter conditions, they examined the behavior of synoptic and planetary waves growing in moist and dry environments. Surface conditions were representative of a zonally averaged ocean. They found that moist convection associated with baroclinic wave development was confined to the subtropics.
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... flow. Precipitation generated in the latter flow evaporates in the colder dry air and cloud layers merge. ... surfaces. Bleck discusses two numerical methods for constructing isentropic trajectories which include the release of latent... more
... flow. Precipitation generated in the latter flow evaporates in the colder dry air and cloud layers merge. ... surfaces. Bleck discusses two numerical methods for constructing isentropic trajectories which include the release of latent heat. ...
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A model ocean composed of four isopycnic layers on a beta plane is spun up from rest by anticyclonic wind stress. Model equations are formulated in material isopycnic coordinates with no restrictions againist vanishing layer thickness.... more
A model ocean composed of four isopycnic layers on a beta plane is spun up from rest by anticyclonic wind stress. Model equations are formulated in material isopycnic coordinates with no restrictions againist vanishing layer thickness. This permits separation of the western boundary current from the coastline and formation of coastal upwelling fronts. The optimum truncation properties of isopycnic coordinates with regard to frontogenesis are discussed and weighted against numerical stability problems associated with the outcropping of isopycnals at the sea surface. Examples of coastal upwelling fronts are presented.
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Research Interests: Collective Behavior, Environmental Science, Geology, Oceanography, Climatology, and 15 moreHeat Transfer, Heat Exchanger, Sea surface temperature, Climate Dynamics, Atmospheric sciences, North Atlantic, Ocean Circulation, Thermohaline Circulation, Random Noise, General Circulation Models, Forcing, Gulf Stream, Atmospheric Temperature, surface air temperature, and surface temperature
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Abstract This paper describes a 30-yr spinup experiment of the North Atlantic Ocean with the Miami isopycnic-coordinate ocean model, which, when compared with previous experiments, possesses improved horizontal resolution, surface forcing... more
Abstract This paper describes a 30-yr spinup experiment of the North Atlantic Ocean with the Miami isopycnic-coordinate ocean model, which, when compared with previous experiments, possesses improved horizontal resolution, surface forcing functions, and bathymetry, and is extended to higher latitudes. Overall, there is a conversion of lighter to heavier water masses, and waters of densities 1027.95 and 1028.05 kg m−3 are produced in the Greenland-lceland Norwegian basin, and of density 1027.75 kg m−3 in the Labrador and Irminger basins. These water masses flow primarily southward. The main purpose of this present study, however, is to investigate the ventilation of the subtropical gyre. The role of Ekman pumping and lateral induction in driving the subduction process is examined and the relative importance of the latter is confirmed. The paper also illustrates how the mixed layer waters are drawn southward and westward into the ocean interior in a continuous spectrum of mode waters with densities ranging ...