Jacob Daniel J.

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Jacob
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Daniel J.
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  • Article
    The United States' next generation of atmospheric composition and coastal ecosystem measurements : NASA's Geostationary Coastal and Air Pollution Events (GEO-CAPE) Mission
    (American Meteorological Society, 2012-10) Fishman, J. ; Iraci, L. T. ; Al-Saadi, J. ; Chance, K. ; Chavez, Francisco P. ; Chin, M. ; Coble, Paula G. ; Davis, Curtiss O. ; DiGiacomo, P. M. ; Edwards, D. ; Eldering, A. ; Goes, Joachim I. ; Herman, J. ; Hu, Chuanmin ; Jacob, Daniel J. ; Jordan, C. ; Kawa, S. Randolph ; Key, R. ; Liu, X. ; Lohrenz, Steven E. ; Mannino, Antonio ; Natraj, V. ; Neil, D. ; Neu, J. ; Newchurch, M. J. ; Pickering, K. ; Salisbury, Joseph E. ; Sosik, Heidi M. ; Subramaniam, A. ; Tzortziou, Maria ; Wang, Jian ; Wang, M.
    The Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission was recommended by the National Research Council's (NRC's) Earth Science Decadal Survey to measure tropospheric trace gases and aerosols and coastal ocean phytoplankton, water quality, and biogeochemistry from geostationary orbit, providing continuous observations within the field of view. To fulfill the mandate and address the challenge put forth by the NRC, two GEO-CAPE Science Working Groups (SWGs), representing the atmospheric composition and ocean color disciplines, have developed realistic science objectives using input drawn from several community workshops. The GEO-CAPE mission will take advantage of this revolutionary advance in temporal frequency for both of these disciplines. Multiple observations per day are required to explore the physical, chemical, and dynamical processes that determine tropospheric composition and air quality over spatial scales ranging from urban to continental, and over temporal scales ranging from diurnal to seasonal. Likewise, high-frequency satellite observations are critical to studying and quantifying biological, chemical, and physical processes within the coastal ocean. These observations are to be achieved from a vantage point near 95°–100°W, providing a complete view of North America as well as the adjacent oceans. The SWGs have also endorsed the concept of phased implementation using commercial satellites to reduce mission risk and cost. GEO-CAPE will join the global constellation of geostationary atmospheric chemistry and coastal ocean color sensors planned to be in orbit in the 2020 time frame.
  • Article
    Global oceanic emission of ammonia : constraints from seawater and atmospheric observations
    (John Wiley & Sons, 2015-08-13) Paulot, Fabien ; Jacob, Daniel J. ; Johnson, Martin T. ; Bell, Tom G. ; Baker, Alexander R. ; Keene, William C. ; Lima, Ivan D. ; Doney, Scott C. ; Stock, Charles A.
    Current global inventories of ammonia emissions identify the ocean as the largest natural source. This source depends on seawater pH, temperature, and the concentration of total seawater ammonia (NHx(sw)), which reflects a balance between remineralization of organic matter, uptake by plankton, and nitrification. Here we compare [NHx(sw)] from two global ocean biogeochemical models (BEC and COBALT) against extensive ocean observations. Simulated [NHx(sw)] are generally biased high. Improved simulation can be achieved in COBALT by increasing the plankton affinity for NHx within observed ranges. The resulting global ocean emissions is 2.5 TgN a−1, much lower than current literature values (7–23 TgN a−1), including the widely used Global Emissions InitiAtive (GEIA) inventory (8 TgN a−1). Such a weak ocean source implies that continental sources contribute more than half of atmospheric NHx over most of the ocean in the Northern Hemisphere. Ammonia emitted from oceanic sources is insufficient to neutralize sulfate aerosol acidity, consistent with observations. There is evidence over the Equatorial Pacific for a missing source of atmospheric ammonia that could be due to photolysis of marine organic nitrogen at the ocean surface or in the atmosphere. Accommodating this possible missing source yields a global ocean emission of ammonia in the range 2–5 TgN a−1, comparable in magnitude to other natural sources from open fires and soils.
  • Article
    Precision requirements for space-based XCO2 data
    (American Geophysical Union, 2007-05-26) Miller, C. E. ; Crisp, D. ; DeCola, P. L. ; Olsen, S. C. ; Randerson, James T. ; Michalak, Anna M. ; Alkhaled, A. ; Rayner, Peter ; Jacob, Daniel J. ; Suntharalingam, Parvadha ; Jones, D. B. A. ; Denning, A. S. ; Nicholls, M. E. ; Doney, Scott C. ; Pawson, S. ; Boesch, H. ; Connor, B. J. ; Fung, Inez Y. ; O'Brien, D. ; Salawitch, R. J. ; Sander, S. P. ; Sen, B. ; Tans, Pieter P. ; Toon, G. C. ; Wennberg, Paul O. ; Wofsy, Steven C. ; Yung, Y. L. ; Law, R. M.
    Precision requirements are determined for space-based column-averaged CO2 dry air mole fraction (XCO2) data. These requirements result from an assessment of spatial and temporal gradients in XCO2, the relationship between XCO2 precision and surface CO2 flux uncertainties inferred from inversions of the XCO2 data, and the effects of XCO2 biases on the fidelity of CO2 flux inversions. Observational system simulation experiments and synthesis inversion modeling demonstrate that the Orbiting Carbon Observatory mission design and sampling strategy provide the means to achieve these XCO2 data precision requirements.