Middle East AOD550 Forecasts and Observations in 2018 and 2019

This dataset is used in a study (Lee et al. 2021) in which we compared total aerosol forecasts in the Middle East from three publicly available models, from NASA and NOAA in the U.S. and from CAMS in Europe. We used forecasts issued twice daily during all of 2018 and 2019. From each model run we validated forecasts of total aerosol optical depth at 550 nm (AOD550) against observations made from 20 ground-based AERONET stations across the region. We found that the NASA GEOS-5 model performed the best overall in the Middle East, the CAMS NRT model was second-best, and the NOAA NGAC model generally performed poorly. Because dust storms are a relatively common phenomenon in the Middle East and bring significant disruptions both to solar power generation and to society in general, we also examined how well the three forecast models performed during two dust storm events. GEOS-5 model forecast data: 14.8 GB total, .nc4 format, models initialized at 00 & 12 UTC daily from 1 January 2018 to 31 December 2019, with 1-hourly forecasts (out to 240 hours for 00 UTC cycles, and 120 hours for 12 UTC cycles), 105 latitude points (16.0 degree N to 42.0 degree N, 0.25 degree grid spacing) x 135 longitude points (24.0625 degree E to 65.9375 degree E, 0.3125 degree grid spacing). One file per forecast valid time. Variable: Total aerosol optical extinction at 550 nm. Recent GEOS-5 data can be freely downloaded from https://www.nccs.nasa.gov/services/data-collections/coupled-products/geos5-forecast. NGAC model forecast data: 1.1 GB total, .grib2 format, models initialized at 00 & 12 UTC daily from 1 January 2018 to 31 December 2019, with 3-hourly forecasts out to 120 hours, 27 latitude points (16.0 degree N to 42.0 degree N, 1.0 degree grid spacing) x 43 latitude points (24.0 degree E to 66.0 degree E, 1.0 degree grid spacing). One file per forecast cycle (contains all lead times). Variable: Total aerosol optical depth at 550 nm. Limited NGAC data can be freely downloaded from https://www.nco.ncep.noaa.gov/pmb/products/ngac. CAMS NRT model forecast data: 559 GB total, netCDF format, models initialized at 00 & 12 UTC daily from 1 January 2018 to 31 December 2019, with 1-hourly forecasts out to 120 hours, global data at 0.4 degree grid spacing (i.e., not geographically subsetted). One file per forecast valid time. Variable: Total aerosol optical depth at 550 nm. NOTE: Archived CAMS NRT data are only available publicly every 3 hours, so the in-between times were processed as linear interpolations between surrounding 3-hourly times. File variables and names were also processed to mimic the files that can be downloaded in real-time from CAMS. CAMS data is subject to this license: https://www.regional.atmosphere.copernicus.eu/doc/CAMS_data_license_final.pdf. 3-hourly archived CAMS data can be freely downloaded from https://apps.ecmwf.int/datasets/data/cams-nrealtime/levtype=sfc/. AERONET observation data: 77 MB total, .csv format, daily-average, 1-hour average, and instantaneous L1.5 data (and L2 data when available) from 20 AERONET sites in the Middle East: Tuz_Golu_3 and IMS-METU-ERDEMLI in Turkey; Nicosia, AgiaMarina_Xyliatou, and CUT-TEPAK in Cyprus; Migal, Technion_Haifa_IL, Wiezmann_Institute, SEDE_BOKER, and Eilat in Israel; Cairo_EMA_2, El_Farafra, and Qena_SVU in Egypt; KAUST_Campus in Saudi Arabia; IASBS in Iran; Shagaya_Park and Kuwait_University in Kuwait; and Mezaira, Masdar_Institute, and DEWA_ResearchCentre in UAE. Date range: 1 January 2018 to 2 January 2020. L1 (raw) data is also provided from 1 to 31 July 2018 at Mezaira, and from 20 to 30 April 2018 at Shagaya_Park to span two dust storm events. Variables: Total aerosol optical depth at 550 nm and Angstrom exponent. AERONET data can be freely downloaded from https://aeronet.gsfc.nasa.gov/new_web/data.html.