Data coverage
Deep Space Climate Observatory (DSCOVR) DSCOVR National Institute of Standards and Technology Advanced Radiometer (NISTAR) was explicitly designed to measure the global daytime radiation budget for an entire hemisphere using active cavity radiometers for three channels: total (0.2 - 100 um), SW (0.2 - 4.0 um), and near-infrared (0.7 - 4.0 um). To derive the Earth Radiation Budget (ERB) from NISTAR measurements, the Short Wave (SW) radiances need to be unfiltered first before they can be subtracted from the total to yield the Long Wave (LW) (4 - 100 um) radiances. Additionally, the Earth's surface and atmosphere are anisotropic reflectors and emitters, resulting in a relatively complex variation of radiance leaving the Earth as a function of viewing and illumination. Converting radiance to flux requires using angular distribution models (ADMs) to account for the emittance and reflectance anisotropies. The anisotropies are characterized for all Earth Polychromatic Imaging Camera (EPIC) pixels by using the Clouds and the Earth's Radiant Energy System (CERES) empirical angular distribution models (ADMs), which are functions of scene types which are defined using many variables including surface type, cloud amount, cloud phase, and optical depth, and water vapor. EPIC composite product is used to provide accurate scene-type information. The EPIC composites are generated from cloud property retrievals from Low Earth Orbit/Geostationary Equatorial Orbit (LEO/GEO) imagers mapped into the EPIC pixels. The EPIC composite also includes ancillary data (i.e., surface type, snow and ice map, skin temperature, precipitable water, etc.) needed for anisotropic factor selections. The anisotropies at the EPIC-pixel are then used to calculate the global mean SW and LW anisotropic factors, then convert the NISTAR SW and LW radiances to fluxes. This product contains the time series of the daytime Earth radiation budget derived from the NISTAR measurements. DSCOVRNISTARL1A DSCOVRNISTARL1A is the Deep Space Climate Observatory (DSCOVR) National Institute of Standards & Technology Advanced Radiometer (NISTAR) Level 1A Radiance, Version 3 data product. NISTAR is a 4-band radiometer onboard THE National Oceanic and Atmospheric Administration's (NOAA) DSCOVR spacecraft located at the Earth-Sun Lagrange-1 (L-1) point, from which vantage it continuously measures the reflected and emitted radiances of the sunlit face of the Earth. These measurements provide an accurate energy balance measurement that improves our understanding of the Earth's radiation budget. NISTAR employs three electrical substitution radiometers and a photodiode to measure reflected sunlight and infrared emission from the Earth. NISTAR measures the absolute irradiance integrated over the entire sunlit face of Earth in four broadband channels minute-by-minute. NISTAR has a 1º field of view (FOV) that acts as one large pixel that encompasses the entire sunlit side of the Earth and a 7º field of regard. The four measurement bands and their uses are: 1) Total Radiation – 0.2 µm to 100 µm: total radiant power in the UV, visible, and infrared wavelengths emerging from Earth. 2) Total Solar Reflected – 0.2 µm to 4 µm: reflected solar radiance in UV, visible, and near-infrared wavelengths from Earth. 3) Near Infrared Solar Reflected – 0.7 µm to 4 µm: reflected near-infrared solar radiation from Earth. 4) Photodiode – 0.2 µm to 1.1 µm: tracks the stability of the filters and verifies co-alignment of NISTAR and EPIC. The Level 1A products have been converted to engineering units but retain one-to-one associations with the items in the raw telemetry from which they were derived. These data products are in HDF5 format. DSCOVREPICL2O3SO2AI Robust cloud products are critical for the Deep Space Climate Observatory (DSCOVR) to contribute significantly to climate studies. Building on our team’s track record in cloud detection, cloud property retrieval, oxygen band exploitation, and DSCOVR-related studies, we propose to develop a suite of algorithms for generating the operational Earth Polychromatic Imaging Camera (EPIC) cloud mask, cloud height, and cloud optical thickness products. Multichannel observations will be used for cloud masking; the cloud height will be developed with information from the oxygen A- and B- band pairs (780 nm vs. 779.5 nm and 680 nm vs. 687.75 nm); for the cloud optical thickness retrieval, we propose an approach that combines the EPIC 680 nm observations and numerical weather model outputs. Preliminary results from radiative transfer modeling and proxy data applications show that the proposed algorithms are viable. Product validation will be conducted by comparing EPIC observations/retrievals with counterparts from coexisting Low Earth Orbit (LEO) and Geosynchronous Earth Orbit (GEO) satellites. The proposed work will include a rigorous uncertainty analysis based on theoretical and computational radiative transfer modeling that complements standard validation activities with physics-based diagnostics. We also plan to evaluate and improve the calibration of the EPIC O2 A- and B-band absorption channels by tracking the instrument performance over known targets, such as cloud-free ocean and ice sheet surfaces. The deliverables for the proposed work include an Algorithm Theoretical Basis Document (ATBD) for peer review, products generated with the proposed algorithms, and supporting research articles. The data products, archived at the Atmospheric Science Data Center (ASDC) at the NASA Langley Research Center, will provide essential inputs needed for the community to apply EPIC observations to climate research and better interpret The National Institute of Standards and Technology Advanced Radiometer (NISTAR) observations. The proposed work directly responds to the solicitation to “develop and implement the necessary algorithms and processes to enable various data products from EPIC sunrise to sunset observations once on orbit” and improve “the calibration of EPIC based on in-flight data.” DSCOVREPICL1AMISC The Deep Space Climate Observatory (DSCOVR) mission's Earth Polychromatic Imaging Camera (EPIC) Level 1A miscellaneous data products capture unique images of the Moon transiting across the Earth's disk, dark space or Jupiter from the spacecraft's position at Lagrange point L1. These specialized observations, stored in HDF5 format, contain calibrated radiance measurements across 10 spectral bands ranging from 317 nm (ultraviolet) to 780 nm (near-infrared). The images of the Moon transiting across the Earth's disk or appearing alongside Earth included in the miscellaneous dataset provide a distinctive perspective of the Earth-Moon system from approximately one million miles away, offering valuable information for Earth-Moon system dynamics. DSCOVREPICL2TO3 DSCOVREPICL2TO3v03 is Level2 Total Ozone derived from the Deep Space Climate Observatory (DSCOVR) Earth Polychromatic Imaging Camera (EPIC) using Level 1b version 3 inputs and version 3 ozone retrieval algorithm. The measurements from four EPIC UV (ultraviolet) channels derive the global distributions of total ozone over the entire sunlit portion of the Earth. A new soft calibration technique developed based on scene matching with OMPS gives calibrated EPIC radiances. The calibrated EPIC radiances derive science-quality total ozone products from EPIC consistent with those from other UV instruments. The retrieval algorithm uses wavelength triplets and assumes that the scene reflectivity changes linearly with wavelength. Version 3 algorithm includes several key modifications aimed to improve total ozone retrievals: a) switch to Version 3 Level 1b product with improved geolocation registration, flat field, and dark counts corrections; b) replace OMI-based (Ozone Monitoring Instrument) cloud height climatology with the simultaneous EPIC A-Band cloud height; c) update absolute calibrations using polar orbiting the NASA OMPS SNPP ( Ozone Mapping and Profil
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