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Development of the OSSE framework was based on three overarching goals: (1) the nature run must\n\t\t\t\t\t\tprovide a reasonable representation of the real atmosphere; (2) the observation simulator must\n\t\t\t\t\t\tbe able to produce synthetic \u201cmeasurements\u201d that account for the spectral resolution, signal to\n\t\t\t\t\t\tnoise ratio, and averaging kernel (AK, sensitivity of measurement to true state) of the\n\t\t\t\t\t\tinstrument being assessed; and (3) the model used within the data assimilation system should be\n\t\t\t\t\t\tdifferent than the model used to generate the nature atmosphere. The first two years of the\n\t\t\t\t\t\tRegional\/Urban OSSE activities focused on completion of ultraviolet (UV) visible (VIS) and thermal infrared\n\t\t\t\t\t\t(TIR) radiative transfer (RT) modeling, generation of multi-spectral retrievals for a subset of\n\t\t\t\t\t\tCONUS profiles, and AK regression to extend the training set to all of North America for the O3\n\t\t\t\t\t\tOSSE studies.<\/p>\n\n\n\n
The Regional\/Urban OSSE Working Group activities resulted in \nseveral innovations. A hyperspectral\n\t\t\t\t\t\tsurface reflectivity\/emissivity database was created that combined\n GOME, MODIS and ASTER\n\t\t\t\t\t\tmeasurements with dual regression fitting for the spectral gap \nbetween the near-infrared and the\n\t\t\t\t\t\tthermal infrared. A multiple linear regression method was \ndeveloped to provide O3 retrievals\n\t\t\t\t\t\tover the entire CONUS region from selected full optimal estimation\n retrievals. Since NO2 and\n\t\t\t\t\t\tHCHO have significantly more spatial and temporal variability than\n O3, the fast Two Stream Exact Single Scattering (2S-ESS) Radiatie \nTransfer (RT) model\n\t\t\t\t\t\twas developed to avoid regression but instead perform full optimal\n estimation retrievals for\n\t\t\t\t\t\tevery cloud free grid point of the nature run. This approach \nresulted in a 200-fold speed\n\t\t\t\t\t\tincrease compared to the full multiple scattering LIDORT RT model \nwith negligible loss of\n\t\t\t\t\t\taccuracy. A new aerosol single scattering property database was \ncreated for six aerosol types\n\t\t\t\t\t\t(black carbon, dust, nitrate, insoluble and soluble organic carbon\n and sulfate) that spanned the\n\t\t\t\t\t\tentire ultraviolet to thermal infrared wavelength range and \naccounted for hygroscopic\n\t\t\t\t\teffects.<\/p>\n\n\n\n
The results were presented at the\n\t\t\t\t\t\tSecond Atmopsheric Composition OSSE Workshop, which was hosted by \nthe European Center for Medium\n\t\t\t\t\t\tRange Weather Forecasting in Reading, UK from 9\u201311 November, 2016.\n The GEO-CAPE Regional O3 OSSE\t\t\t\t\t demonstrates systematic and \nsignificant increase in lower to mid tropospheric correlations and\n\t\t\t\t\t\treductions in root mean square (rms) errors and biases when hourly\n geostationary UV\/VIS, and\n\t\t\t\t\t\tUV\/VIS\/TIR ozone retrievals are assimilated, compared to UV-only \nmeasurements. Results show\n\t\t\t\t\t\timprovements in lower tropospheric correlations and rms errors for\n all experiments, but the UV\n\t\t\t\t\t\tand UV\/VIS experiments introduce higher biases. Comparisons with \nthe nature run at US\n\t\t\t\t\t\tEnvironmental Protection Agency surface monitoring sites show that\n the overall positive impacts\n\t\t\t\t\t\tobtained with UV\/VIS\/TIR retrieval assimilation are due to \nreductions in nighttime biases, which\n\t\t\t\t\t\thighlights the importance of the TIR measurements in the \nmulti-spectral retrievals. A manuscript\n\t\t\t\t\tdescribing the O3 OSSE is currently in prepartion (Pierce et al., \n2018).<\/p>\n\n\n\n
We have also completed the NO2 OSSE and are nearing completion of the HCHO OSSE. Using the 2S-ESS\n\t\t\t\t\t\tRT model, we were able to generate synthetic radiances for all cloud free gridpoints at hourly\n\t\t\t\t\t\tintervals for the full nature run timeperiod (July 2011) utilizing the Supercomputer for\n\t\t\t\t\t\tSatellite Simulations and Data Assimilation Studies (Boukabara et al, 2016) at the University of\n\t\t\t\t\t\tWisconsin-Madison Space Science and Engineering Center. Since NO2 and HCHO are short lived\n\t\t\t\t\t\tspecies, assimilation of NO2 or HCHO column retrievals does not lead to systematic changes in\n\t\t\t\t\t\tthe concentrations of these species. Instead, the NO2 and HCHO column retrievals must be used to\n\t\t\t\t\t\tconstrain the emissions of these species. As part of the Regional\/Urban OSSE working group\n\t\t\t\t\t\tactivities during 2015\u20132018 we developed an offline approach to use satellite based trace gas\n\t\t\t\t\t\tretrievals to constrain area and point source emissions. The approach involves calculating the\n\t\t\t\t\t\tsensitivity of the trace gas column to changes in emissions following Lamsal et al. (2011) and\n\t\t\t\t\t\tthen using this sensitivity, combined with the monthly mean trace gas analysis increment, to\n\t\t\t\t\t\tadjust the emissions. The results of the NO2 OSSE were presented at the Joint Committee on Earth\n\t\t\t\t\t\tObservation Satellites Atmospheric Composition-Virtual Constellation and GEO-CAPE Meeting, which\n\t\t\t\t\t\twas hosted by the NOAA Center for Weather and Climate Prediction in College Park, MD from May\n\t\t\t\t\t\t2\u20134, 2018. The GEOCAPE NO2 OSSE demonstrates significant adjustments in a priori NOx emissions\n\t\t\t\t\t\tusing hourly TEMPO-like NO2 retrievals compared to daily OMI NO2 emission adjustments. However,\n\t\t\t\t\t\tthe NO2 OSSE results show low surface ozone sensitivity to changes in NOx emissions, possibly\n\t\t\t\t\t\tdue to high urban NOx levels leading to VOC sensitive ozone production. The O3, NO2, and HCHO\n\t\t\t\t\t\tassimilation experiments were conducted using the NOAA gridpoint statistical interpolation (GSI;\n\t\t\t\t\t\tWu et al., 2002; Kleist et al., 2009), which is a physical space-based 3-dimensional variational\n\t\t\t\t\t\tanalysis. The observation operator for the O3, NO2, and HCHO profile retrievals was developed\n\t\t\t\t\t\tfor GSI based on the approach used by Verma et al. (2009) for assimilation of ozone profiles\n\t\t\t\t\t\tfrom the Tropospheric Emission Spectrometer. This observation operator accounts for the AK and a\n\t\t\t\t\t\tpriori used in the retrieval.<\/p>\n","protected":false},"excerpt":{"rendered":"
The GEO-CAPE Regional\/Urban Observation System Simulation Experiment (OSSE) Working Group was initiated in 2013 to assess the value of geostationary observations of ozone (O3), nitrogen dioxide (NO2) and formaldehyde (HCHO) over the continental US (CONUS) in addressing the scientific and applications objectives of GEO-CAPE. The main components of the Regional\/Urban OSSE (nature run, observation simulator, […]<\/p>\n","protected":false},"author":58,"featured_media":0,"parent":22,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-30","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.ssec.wisc.edu\/staff\/wp-json\/wp\/v2\/pages\/30","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ssec.wisc.edu\/staff\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.ssec.wisc.edu\/staff\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.ssec.wisc.edu\/staff\/wp-json\/wp\/v2\/users\/58"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ssec.wisc.edu\/staff\/wp-json\/wp\/v2\/comments?post=30"}],"version-history":[{"count":1,"href":"https:\/\/www.ssec.wisc.edu\/staff\/wp-json\/wp\/v2\/pages\/30\/revisions"}],"predecessor-version":[{"id":32,"href":"https:\/\/www.ssec.wisc.edu\/staff\/wp-json\/wp\/v2\/pages\/30\/revisions\/32"}],"up":[{"embeddable":true,"href":"https:\/\/www.ssec.wisc.edu\/staff\/wp-json\/wp\/v2\/pages\/22"}],"wp:attachment":[{"href":"https:\/\/www.ssec.wisc.edu\/staff\/wp-json\/wp\/v2\/media?parent=30"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}