# Satellite Climate Data Records: Development, Applications, and Societal Benefits
## 3 CDR Products and Applications
### CDRs and Scientific Applications
#### 3.1.1 NOAA Climate Data Record Program
These data comprise an estimate of the fraction of ocean area covered by sea ice that is produced by combining concentration estimates created using two algorithms developed at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC). Gridded brightness temperatures acquired from a number of DMSP passive microwave radiometers provide the necessary input to produce the CDR. The product has applications that include studying and monitoring climate variability and providing guidance for the industries of shipping and fisheries. * _Sea Surface Temperature_--_Optimum Interpolation_: The NOAA 1/4\({}^{\circ}\) daily Optimum Interpolation Sea Surface Temperature (or daily OISST) provides complete ocean temperature fields constructed by combining bias-adjusted observations from different platforms (satellite, ships, buoys) on a regular global grid, with gaps filled in by the interpolation [23]. Satellite data from AVHRR provides the main input which permits the high temporal-spatial coverage beginning in late 1981 to the present; this must be adjusted to the buoys due to erroneous cold SSTs following the Mt Pinatubo and El Chichon eruptions. Applications include climate modeling, resource management, ecological studies on annual to daily scales [61]. * _AVHRR Surface Reflectance_: Surface reflectance provides a measure of the fraction of incoming solar radiation that is reflected from Earth's surface in two spectral ranges of the AVHRR sensors: red (around 0.64 \(\upmu\)m) and the near infrared (around 0.86 \(\upmu\)m). As a key variable, surface reflectance supplies the primary input for essentially all higher-level land surface geophysical parameters, such as NDVI and LAI CDRs. The surface reflectance CDR delivers valuable surface information dating back to 1981 as a daily product on a 0.05\({}^{\circ}\) grid [62]. It has been used to study long-term climate variability along with climate model verification and validation. * _Land Area Index and FAPAR_: The Leaf Area Index (LAI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) are biophysical variables that characterize the canopy and photosynthetic activity of plants. The one-sided green leaf area per unit ground surface area describes the LAI dataset. The fraction of the incoming solar radiation in the Photosynthetically Active Radiation spectral region that is absorbed by the plants defines the FAPAR data set. The LAI/FAPAR CDR is a daily product on a 0.05\({}^{\circ}\) grid from 1981 to present derived from AVHRR sensors [62]. It can be used to evaluate vegetation stress and forecast agricultural yields [63; 64]. * _Normalized Difference Vegetation Index_: The Normalized Difference Vegetation Index (NDVI) CDR summarizes the measurement of surface vegetation coverage. The surface reflectance calculations in the red and the near infrared spectral bands derived from AVHRR provide NDVI values [62]. The NDVI CDR produces daily output on a 0.05\({}^{\circ}\) grid, from 1981 to present. This consistent, long-term record of remotely sensed vegetation observations allows scientists to characterize the health of vegetation in different regions across the world [63; 64]. * _Snow Cover Extend (Northern Hemisphere)_: The weekly Northern Hemisphere (NH) Snow Cover Extend (SCE) CDR spans the period from late 1966 to present, comprising the longest satellite-based CDR of any environmental variable. This CDR combines the NOAA visible satellite-based SCE analyses generated weekly through May 1999 and daily since June 1999 to form a continuous NH record [65]. The resulting continental SCE product informs climate studies, climate change monitoring, and climate model validation [66; 67].