17 results on '"Westberg, David J."'
Search Results
2. Airborne measurements of cirrus‐activated C2Cl4 depletion in the upper troposphere with evidence against Cl reactions
- Author
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Simpson, Isobel J, Wingenter, Oliver W, Westberg, David J, Fuelberg, Henry E, Kiley, Christopher M, Crawford, James H, Meinardi, Simone, Blake, Donald R, and Rowland, F Sherwood
- Subjects
Earth Sciences ,Atmospheric Sciences ,tetrachloroethene ,chlorine activation ,heterogeneous chemistry ,TRACE-P ,cirrus ,Meteorology & Atmospheric Sciences - Abstract
Airborne whole air samples collected over the western Pacific in spring, 2001 showed depletion of tetrachloroethene (C2Cl4) in every upper tropospheric (UT) air parcel that had interacted with large areas of cirrus less than three days upwind. The amount of C2Cl4 depletion showed a negative correlation with time since the interaction, consistent with the C2Cl4-depleted air parcels mixing with the ambient air as they moved downwind of the cirrus. Ethane and C2Cl4 both react relatively quickly with atomic chlorine (Cl) but ethane was not significantly depleted in these same air parcels, indicating that the C2Cl4 depletion cannot be attributed to Cl chemistry alone. Based on the minimum ethane depletion that can be detected by our measurements, a daytime upper limit of roughly 3 × 104 atom Cl cm-3 is indirectly estimated for heterogeneous chlorine activation by cirrus clouds in the UT in tropical- and mid-latitudes during spring. © 2003 by the American Geophysical Union.
- Published
- 2003
3. Chemical transport across the ITCZ in the central Pacific during an El Niño‐Southern Oscillation cold phase event in March‐April 1999
- Author
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Avery, Melody A, Westberg, David J, Fuelberg, Henry E, Newell, Reginald E, Anderson, Bruce E, Vay, Stephanie A, Sachse, Glen W, and Blake, Donald R
- Subjects
Meteorology & Atmospheric Sciences - Abstract
We examine interhemispheric transport processes that occurred over the central Pacific during the PEM-Tropics B mission (PTB) in March-April 1999 by correlating the observed distribution of chemical tracers with the prevailing and anomalous windfields. The Intertropical Convergence Zone (ITCZ) had a double structure during PTB, and interhemispheric mixing occurred in the equatorial region between ITCZ branches. The anomalously strong tropical easterly surface wind had a large northerly component across the equator in the central Pacific, causing transport of aged, polluted air into the Southern Hemisphere (SH) at altitudes below 4 km. Elevated concentrations of chemical tracers from the Northern Hemisphere (NH) measured south of the equator in the central Pacific during PTB may represent an upper limit because the coincidence of seasonal and cold phase ENSO conditions are optimum for this transport. Stronger and more consistent surface convergence between the northeasterly and southeasterly trade winds in the Southern Hemisphere (SH) resulted in more total convective activity in the SH branch of the ITCZ, at about 6° S. The middle troposphere between 4-7 km was a complex shear zone between prevailing northeasterly winds at low altitudes and southwesterly winds at higher altitudes. Persistent anomalous streamline patterns and the chemical tracer distribution show that during PTB most transport in the central Pacific was from SH to NH across the equator in the upper troposphere. Seasonal differences in source strength caused larger interhemispheric gradients of chemical tracers during PTB than during the complementary PEM-Tropics A mission in September-October 1996. Copyright 2001 by the American Geophysical Union.
- Published
- 2001
4. A meteorological overview of the Pacific Exploratory Mission (PEM) Tropics period
- Author
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Fuelberg, Henry E, Newell, Reginald E, Longmore, Scott P, Zhu, Yong, Westberg, David J, Browell, Edward V, Blake, Donald R, Gregory, Gerald L, and Sachse, Glen W
- Subjects
Climate Action ,Meteorology & Atmospheric Sciences - Abstract
NASA's Pacific Exploratory Mission-Tropics (PEM-T) experiment investigated the atmospheric chemistry of a large portion of the tropical and subtropical Pacific Basin during August to October 1996. This paper summarizes meteorological conditions over the PEM-T domain. Mean flow patterns during PEM-T are described. Important circulation systems near the surface include subtropical anticyclones, the South Pacific Convergence Zone (SPCZ), the Intertropical Convergence Zone (ITCZ), and middle latitude transient cyclones. The SPCZ and ITCZ are areas of widespread ascent and deep convection; however, there is relatively little lightning in these oceanic regions. A large area of subsidence is associated with the subtropical anticyclone centered near Easter Island. PEM-T occurred during a period of near normal sea surface temperatures. When compared to an 11 year climatology (1986-1996), relatively minor circulation anomalies are observed during PEM-T. Some of these circulation anomalies are consistent with much stronger anomalies observed during previous La Nina events. In general, however, the 1996 PEM-T period appears to be climatologically representative. Meteorological conditions for specific flights from each major operations area are summarized. The vertical distribution of ozone along selected DC-8 flights is described using the DIAL remote sensing system. These ozone distributions are related to thermodynamic soundings obtained during aircraft maneuvers and to backward trajectories that arrived at locations along the flight tracks. Most locations in the deep tropics are found to have relatively small values of tropospheric ozone. Backward trajectories calculated from global gridded analyses show that much of this air originates from the east and has not passed over land within 10 days. The deep convection associated with the ITCZ and SPCZ also influences the atmospheric chemistry of these regions. Flights over portions of the subtropics and middle latitudes document layers of greatly enhanced tropospheric ozone, sometimes exceeding 80 ppbv. In situ carbon monoxide in these layers often exceeds 90 ppbv. These regions are located near, and especially south of Tahiti, Easter Island, and Fiji. The layers of enhanced ozone usually correspond to layers of dry air, associated with widespread subsiding air. The backward trajectories show that air parcels arriving in these regions originate from the west, passing over Australia and even extending back to southern Africa. These are regions of biomass burning. The in situ chemical measurements support the trajectory-derived origins of these ozone plumes. Thus the enhanced tropospheric ozone over the central Pacific Basin may be due to biomass burning many thousands of kilometers away. Middle-latitude portions of the PEM-T area are influenced by transient cyclones, and the DC-8 traversed tropopause folds during several flights. The flight area just west of Ecuador experiences outflow from South America. Thus the biomass burning that is prevalent over portions of Brazil influences this area. Copyright 1999 by the American Geophysical Union.
- Published
- 1999
5. Application of a global-to-beam irradiance model to the NASA GEWEX SRB dataset: An extension of the NASA Surface meteorology and Solar Energy datasets
- Author
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Zhang, Taiping, Stackhouse, Paul W., Jr., Chandler, William S., and Westberg, David J.
- Published
- 2014
- Full Text
- View/download PDF
6. Enhancing the NASA Prediction of Worldwide Energy Resource Web Data Delivery System with Geographic Information System (GIS) Capabilities
- Author
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Chandler, William S, Stackhouse, Paul W., Jr, Barnett, Audy J, Hoell, James M, Westberg, David J, and Ross, Amanda I
- Subjects
Earth Resources And Remote Sensing ,Meteorology And Climatology ,Energy Production And Conversion - Abstract
Renewable energy technologies are changing the face of the world's energy market. Currently, these technologies are being incorporated within existing structures to increase energy efficiency. Crucial to the success of the emerging renewable market is the availability of accurate, global solar radiation, and meteorology data. This poster traces the history of the development of an effort to distribute data parameters from NASA's research for use in the energy sector applications spanning from renewable energy to energy efficiency. These data may be useful to several renewable energy sectors: solar and wind power generation, agricultural crop modeling, and sustainable buildings.
- Published
- 2015
7. Downscaling NASA Climatological Data to Produce Detailed Climate Zone Maps
- Author
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Chandler, William S, Hoell, James M, Westberg, David J, Whitlock, Charles H, Zhang, Taiping, and Stackhouse, P. W
- Subjects
Meteorology And Climatology - Abstract
The design of energy efficient sustainable buildings is heavily dependent on accurate long-term and near real-time local weather data. To varying degrees the current meteorological networks over the globe have been used to provide these data albeit often from sites far removed from the desired location. The national need is for access to weather and solar resource data accurate enough to use to develop preliminary building designs within a short proposal time limit, usually within 60 days. The NASA Prediction Of Worldwide Energy Resource (POWER) project was established by NASA to provide industry friendly access to globally distributed solar and meteorological data. As a result, the POWER web site (power.larc.nasa.gov) now provides global information on many renewable energy parameters and several buildings-related items but at a relatively coarse resolution. This paper describes a method of downscaling NASA atmospheric assimilation model results to higher resolution and maps those parameters to produce building climate zone maps using estimates of temperature and precipitation. The distribution of climate zones for North America with an emphasis on the Pacific Northwest for just one year shows very good correspondence to the currently defined distribution. The method has the potential to provide a consistent procedure for deriving climate zone information on a global basis that can be assessed for variability and updated more regularly.
- Published
- 2011
8. Biogenic Sulfur in the Environment
- Author
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ERIC S. SALTZMAN, WILLIAM J. COOPER, Viney P. Aneja, William J. Cooper, A. Guenther, B. Lamb, H. Westberg, David J. Cooper, William J. Cooper, William Z. de Mello, Eric S. Saltzman, Rod G. Zika, Heinz Rennenberg, Bruce Haines, Marilyn Black, Charlene Bayer, D. A. Dunnette, L. A. Baker, N. R. Urban and ERIC S. SALTZMAN, WILLIAM J. COOPER, Viney P. Aneja, William J. Cooper, A. Guenther, B. Lamb, H. Westberg, David J. Cooper, William J. Cooper, William Z. de Mello, Eric S. Saltzman, Rod G. Zika, Heinz Rennenberg, Bruce Haines, Marilyn Black, Charlene Bayer, D. A. Dunnette, L. A. Baker, N. R. Urban
- Published
- 1989
9. Asian outflow and trans-Pacific transport of carbon monoxide and ozone pollution: An integrated satellite, aircraft, and model perspective
- Author
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Jacob, Daniel J., Fiore, Arlene M., Emmons, Louisa K., Gille, John C., Deeter, Merritt N., Warner, Juying, Edwards, David P., Crawford, James H., Heald, Colette L., Hamlin, Amy J., Sachse, Glen W., Browell, Edward V., Avery, Melody A., Vay, Stephanie A., Westberg, David J., Blake, Donald R., Singh, Hanwant B., Sandholm, Scott T., Talbot, Robert W., and Fuelberg, Henry E.
- Subjects
Meteorology ,Atmospheric chemistry ,Tropospheric chemistry ,Air--Pollution--Measurement ,Satellite meteorology--Data processing ,Climatic changes - Abstract
Satellite observations of carbon monoxide (CO) from the Measurements of Pollution in the Troposphere (MOPITT) instrument are combined with measurements from the Transport and Chemical Evolution Over the Pacific (TRACE-P) aircraft mission over the northwest Pacific and with a global three-dimensional chemical transport model (GEOS-CHEM) to quantify Asian pollution outflow and its trans-Pacific transport during spring 2001. Global CO column distributions in MOPITT and GEOS-CHEM are highly correlated (R2 = 0.87), with no significant model bias. The largest regional bias is over Southeast Asia, where the model is 18% too high. A 60% decrease of regional biomass burning emissions in the model (to 39 Tg yr−1) would correct the discrepancy; this result is consistent with TRACE-P observations. MOPITT and TRACE-P also give consistent constraints on the Chinese source of CO from fuel combustion (181 Tg CO yr−1). Four major events of trans-Pacific transport of Asian pollution in spring 2001 were seen by MOPITT, in situ platforms, and GEOS-CHEM. One of them was sampled by TRACE-P (26–27 February) as a succession of pollution layers over the northeast Pacific. These layers all originated from one single event of Asian outflow that split into northern and southern plumes over the central Pacific. The northern plume (sampled at 6–8 km off California) had no ozone enhancement. The southern subsiding plume (sampled at 2–4 km west of Hawaii) contained a 8–17 ppbv ozone enhancement, driven by decomposition of peroxyacetylnitrate (PAN) to nitrogen oxides (NOx). This result suggests that PAN decomposition in trans-Pacific pollution plumes subsiding over the United States could lead to significant enhancements of surface ozone.
- Published
- 2003
- Full Text
- View/download PDF
10. DERIVING THE DNI FROM THE GHI OF THE NASA GEWEX SRB DATA USING A GLOBAL-TOBEAM MODEL: IMPROVEMENT AND EXTENSION OF THE NASA SSE DATASETS.
- Author
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Taiping Zhang, Stackhouse Jr., Paul W., Chandler, William S., Hoell, James M., and Westberg, David J.
- Subjects
SOLAR energy ,SURFACE meteorology ,REGRESSION analysis ,INTERPOLATION - Abstract
The current version of the NASA Surface meteorology and Solar Energy Datasets, SSE (Rel. 6.0), derived its monthly mean direct normal irradiances (DNIs) directly from the NASA GEWEX SRB (Rel. 3.0) monthly mean global horizontal irradiances (GHIs) and the employed methodology relates the DNI to GHI in terms of monthly mean clearness index, latitudinal range, and solar geometry on the monthly average day. The coefficients of the relations were empirically derived from regression analysis of the BSRN data over the period from 1992 to 2005. While the derived monthly mean SSE (Rel. 6.0) DNIs show reasonable agreement with their BSRN counterparts, improvements in the quality of the dataset and DNIs on shorter time scales were realized through the application of the D1RINDEX model to the 3-hourly GHIs of the NASA GEWEX SRB (Rel. 3.0) data to produce 3- hourly DNIs. The DIRINDEX model is a combination of the DIR1NT model and a simplified version of the SOLIS clear-sky model, and the model was modified to accommodate a wider range of input parameters than originally designed. Additional input parameters include solar geometric, geographic and atmospheric parameters. The results are 3-hourly, daily, and monthly mean DNIs spanning 2000 to 2005 on a quasi-equalarea grid system of 44016 grid cells covering the entire globe. The data are then re-gridded onto a l°x l° grid system for the convenience of users. The resulting monthly mean DNIs show better agreement with the BSRN data than the SSE (Rel. 6.0) DNIs do. To further improve the results, we assimilated the ground-based BSRN data into the DNIs using the inverse-distance interpolation in the latitude-longitude-cosine of solar zenith angle phase space. [ABSTRACT FROM AUTHOR]
- Published
- 2014
11. An Analysis of NASA's MERRA Meteorological Data to Supplement Observational Data for Calculation of Climatic Design Conditions.
- Author
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Westberg, David J., Hoell, James M., Stackhouse Jr, Paul W., Chandler, William S., Crawley, Drury B., and Taiping Zhang
- Subjects
- *
METEOROLOGICAL observations , *DATA analysis , *NUMERICAL calculations , *WIND speed - Abstract
ASHRAE Technical Committee 4.2, Climatic Information, publishes a quadrennial update of climatic design information in Chapter 14 of the ASHRAE Handbook--Fundamentals (ASHRAE 2009a). The design information for 5564 locations around the world is based upon hourly values of dry-bulb temperature, wet-bulb temperature, dew-point temperature, wind speed and direction, surface pressure, and solar radiation. The 2009 design conditions provided a significant enhancement over the 2005 design conditions with respect to the global coverage--564 locations in 2009 versus 4422 locations in 2005. The ASHRAE design conditions, based on meteorological data, are calculated using hourly surface data from stations having a minimum of 8 years of observations, but more stations typically span 25 years of observations; although frequently the time series are discontinuous. The ASHRAE solar-related design conditions are based on model-derived solar radiation. A potential source for both global and time contiguous meteorological and solar data is NASA's POWER (Prediction of Worldwide Energy Resource)web portal (NASA 2013a). This includes the recently available meteorological data based on an improved reanalysis model--Modern Era Retrospective-analysis for Research and Applications (MERRA). MERRA yields global, hourly surface meteorological parameters for the years 1981 to present. An initial evaluation of the MERRA daily maximum, minimum, and averaged temperatures indicates accuracies sufficient to warrant their use to supplement existing surface observations. In this paper, we present an evaluation of the accuracy of the MERRA daily temperatures, followed by an assessment of the applicability of the MERRA hourly temperatures in the development of annual dry-bulb climate design criteria and annual heating and cooling degree-days over the continental United States. [ABSTRACT FROM AUTHOR]
- Published
- 2013
12. Airborne measurements of cirrus‐activated C 2 Cl 4 depletion in the upper troposphere with evidence against Cl reactions
- Author
-
Simpson, Isobel J., primary, Wingenter, Oliver W., additional, Westberg, David J., additional, Fuelberg, Henry E., additional, Kiley, Christopher M., additional, Crawford, James H., additional, Meinardi, Simone, additional, Blake, Donald R., additional, and Rowland, F. Sherwood, additional
- Published
- 2003
- Full Text
- View/download PDF
13. Meteorological conditions and transport pathways during the Transport and Chemical Evolution over the Pacific (TRACE‐P) experiment
- Author
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Fuelberg, Henry E., primary, Kiley, Christopher M., additional, Hannan, John R., additional, Westberg, David J., additional, Avery, Melody A., additional, and Newell, Reginald E., additional
- Published
- 2003
- Full Text
- View/download PDF
14. A meteorological overview of the second Pacific Exploratory Mission in the Tropics
- Author
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Fuelberg, Henry E., primary, Newell, Reginald E., additional, Westberg, David J., additional, Maloney, Joseph C., additional, Hannan, John R., additional, Martin, Brian D., additional, Avery, Melody A., additional, and Zhu, Yong, additional
- Published
- 2001
- Full Text
- View/download PDF
15. Airborne measurements of cirrus-activated C2Cl4 depletion in the upper troposphere with evidence against Cl reactions.
- Author
-
Simpson, Isobel J., Wingenter, Oliver W., Westberg, David J., Fuelberg, Henry E., Kiley, Christopher M., Crawford, James H., Meinardi, Simone, Blake, Donald R., and Rowland, F. Sherwood
- Published
- 2003
- Full Text
- View/download PDF
16. Asian outflow and trans-Pacific transport of carbon monoxide and ozone pollution: An integrated satellite, aircraft, and model perspective
- Author
-
Heald, Colette L., Jacob, Daniel James, Fiore, Arlene M., Emmons, Louisa K., Gille, John C., Deeter, Merritt N., Warner, Juying, Edwards, David P., Crawford, James H., Hamlin, Amy J., Sachse, Glen W., Browell, Edward V., Avery, Melody A., Vay, Stephanie A., Westberg, David J., Blake, Donald R., Singh, Hanwant B., Sandholm, Scott T., Talbot, Robert W., and Fuelberg, Henry E.
- Subjects
TRACE-P ,MOPITT ,Asian pollution ,trans-Pacific transport ,carbon monoxide ,O3 production - Abstract
Satellite observations of carbon monoxide (CO) from the Measurements of Pollution in the Troposphere (MOPITT) instrument are combined with measurements from the Transport and Chemical Evolution Over the Pacific (TRACE-P) aircraft mission over the northwest Pacific and with a global three-dimensional chemical transport model (GEOS-CHEM) to quantify Asian pollution outflow and its trans-Pacific transport during spring 2001. Global CO column distributions in MOPITT and GEOS-CHEM are highly correlated (R2 = 0.87), with no significant model bias. The largest regional bias is over Southeast Asia, where the model is 18% too high. A 60% decrease of regional biomass burning emissions in the model (to 39 Tg yr−1) would correct the discrepancy; this result is consistent with TRACE-P observations. MOPITT and TRACE-P also give consistent constraints on the Chinese source of CO from fuel combustion (181 Tg CO yr−1). Four major events of trans-Pacific transport of Asian pollution in spring 2001 were seen by MOPITT, in situ platforms, and GEOS-CHEM. One of them was sampled by TRACE-P (26–27 February) as a succession of pollution layers over the northeast Pacific. These layers all originated from one single event of Asian outflow that split into northern and southern plumes over the central Pacific. The northern plume (sampled at 6–8 km off California) had no ozone enhancement. The southern subsiding plume (sampled at 2–4 km west of Hawaii) contained a 8–17 ppbv ozone enhancement, driven by decomposition of peroxyacetylnitrate (PAN) to nitrogen oxides (NOx). This result suggests that PAN decomposition in trans-Pacific pollution plumes subsiding over the United States could lead to significant enhancements of surface ozone., Engineering and Applied Sciences
- Published
- 2003
- Full Text
- View/download PDF
17. Airborne measurements of cirrus‐activated C2Cl4depletion in the upper troposphere with evidence against Cl reactions
- Author
-
Simpson, Isobel J., Wingenter, Oliver W., Westberg, David J., Fuelberg, Henry E., Kiley, Christopher M., Crawford, James H., Meinardi, Simone, Blake, Donald R., and Rowland, F. Sherwood
- Abstract
Airborne whole air samples collected over the western Pacific in spring, 2001 showed depletion of tetrachloroethene (C2Cl4) in every upper tropospheric (UT) air parcel that had interacted with large areas of cirrus less than three days upwind. The amount of C2Cl4depletion showed a negative correlation with time since the interaction, consistent with the C2Cl4‐depleted air parcels mixing with the ambient air as they moved downwind of the cirrus. Ethane and C2Cl4both react relatively quickly with atomic chlorine (Cl) but ethane was not significantly depleted in these same air parcels, indicating that the C2Cl4depletion cannot be attributed to Cl chemistry alone. Based on the minimum ethane depletion that can be detected by our measurements, a daytime upper limit of roughly 3 × 104atom Cl cm−3is indirectly estimated for heterogeneous chlorine activation by cirrus clouds in the UT in tropical‐ and mid‐latitudes during spring.
- Published
- 2003
- Full Text
- View/download PDF
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