{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:46:58Z","timestamp":1760237218515,"version":"build-2065373602"},"reference-count":26,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2020,3,13]],"date-time":"2020-03-13T00:00:00Z","timestamp":1584057600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Data from the Advanced Very High Resolution Radiometer (AVHRR) have been used to create several long-duration data records of geophysical variables describing the atmosphere and land and water surfaces. In the Climate Monitoring Satellite Application Facility (CM SAF) project, AVHRR data are used to derive the Cloud, Albedo, and Radiation (CLARA) climate data records of radiation components (i.a., surface albedo) and cloud properties (i.a., cloud cover). This work describes the methodology implemented for the additional estimation of the Outgoing Longwave Radiation (OLR), an important Earth radiation budget component, that is consistent with the other CLARA variables. A first step is the estimation of the instantaneous OLR from the AVHRR observations. This is done by regressions on a large database of collocated observations between AVHRR Channel 4 (10.8 \u00b5m) and 5 (12 \u00b5m) and the OLR from the Clouds and Earth\u2019s Radiant Energy System (CERES) instruments. We investigate the applicability of this method to the first generation of AVHRR instrument (AVHRR\/1) for which no Channel 5 observation is available. A second step concerns the estimation of daily and monthly OLR from the instantaneous AVHRR overpasses. This step is especially important given the changes in the local time of the observations due to the orbital drift of the NOAA satellites. We investigate the use of OLR in the ERA5 reanalysis to estimate the diurnal variation. The developed approach proves to be valuable to model the diurnal change in OLR due to day\/night time warming\/cooling over clear land. Finally, the resulting monthly mean AVHRR OLR product is intercompared with the CERES monthly mean product. For a typical configuration with one morning and one afternoon AVHRR observation, the Root Mean Square (RMS) difference with CERES monthly mean OLR is about 2 Wm\u22122 at 1\u00b0 \u00d7 1\u00b0 resolution. We quantify the degradation of the OLR product when only one AVHRR instrument is available (as is the case for some periods in the 1980s) and also the improvement when more instruments are available (e.g., using METOP-A, NOAA-15, NOAA-18, and NOAA-19 in 2012). The degradation of the OLR product from AVHRR\/1 instruments is also quantified, which is done by \u201cmasking\u201d the Channel 5 observations.<\/jats:p>","DOI":"10.3390\/rs12060929","type":"journal-article","created":{"date-parts":[[2020,3,13]],"date-time":"2020-03-13T08:58:59Z","timestamp":1584089939000},"page":"929","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["The Climate Monitoring SAF Outgoing Longwave Radiation from AVHRR"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2195-8253","authenticated-orcid":false,"given":"Nicolas","family":"Clerbaux","sequence":"first","affiliation":[{"name":"Royal Meteorological Institute of Belgium, B-1180 Brussels, Belgium"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2850-5014","authenticated-orcid":false,"given":"Tom","family":"Akkermans","sequence":"additional","affiliation":[{"name":"Royal Meteorological Institute of Belgium, B-1180 Brussels, Belgium"}]},{"given":"Edward","family":"Baudrez","sequence":"additional","affiliation":[{"name":"Royal Meteorological Institute of Belgium, B-1180 Brussels, Belgium"}]},{"given":"Almudena","family":"Velazquez Blazquez","sequence":"additional","affiliation":[{"name":"Royal Meteorological Institute of Belgium, B-1180 Brussels, Belgium"}]},{"given":"William","family":"Moutier","sequence":"additional","affiliation":[{"name":"Royal Meteorological Institute of Belgium, B-1180 Brussels, Belgium"}]},{"given":"Johan","family":"Moreels","sequence":"additional","affiliation":[{"name":"Royal Meteorological Institute of Belgium, B-1180 Brussels, Belgium"}]},{"given":"Christine","family":"Aebi","sequence":"additional","affiliation":[{"name":"Royal Meteorological Institute of Belgium, B-1180 Brussels, Belgium"}]}],"member":"1968","published-online":{"date-parts":[[2020,3,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1687","DOI":"10.5194\/acp-9-1687-2009","article-title":"Operational climate monitoring from space: The EUMETSAT Satellite Application Facility on Climate Monitoring (CM-SAF)","volume":"9","author":"Schulz","year":"2009","journal-title":"Atmos. Chem. Phys."},{"key":"ref_2","unstructured":"Cracknell, A.P. (1997). Advanced Very High Resolution Radiometer AVHRR, Taylor and Francis."},{"key":"ref_3","first-page":"935","article-title":"CLARA-A1: The CM SAF cloud, albedo and radiation dataset from 28 yr of global AVHRR data","volume":"13","author":"Karlsson","year":"2013","journal-title":"Atmos. Chem. Phys. Discuss."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"5809","DOI":"10.5194\/acp-17-5809-2017","article-title":"CLARA-A2: The second edition of the CM SAF cloud and radiation data record from 34 years of global AVHRR data","volume":"17","author":"Karlsson","year":"2017","journal-title":"Atmos. Chem. Phys."},{"key":"ref_5","first-page":"3","article-title":"PyGAC: An open-source, community-driven Python interface to preprocess more than 30-year AVHRR Global Area Coverage (GAC) data","volume":"11","author":"Devasthale","year":"2017","journal-title":"GSICS Q. Newsl."},{"key":"ref_6","unstructured":"Hollman, R., Schlundt, C., Finkensieper, S., Raspaud, M., Karlsson, K.G., and Stengel, M. (2020, January 31). ESA Cloud cci: Technical Report on AVHRR GAC FCDR Generation. Available online: http:\/\/www.esa-cloud-cci.org\/?q=documentation."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Akkermans, T., and Clerbaux, N. (2020). Narrowband-to-Broadband Conversions for Top-of-Atmosphere Reflectance from the Advanced Very High Resolution Radiometer (AVHRR). Remote Sens., 12.","DOI":"10.3390\/rs12020305"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"853","DOI":"10.1175\/1520-0477(1996)077<0853:CATERE>2.0.CO;2","article-title":"Clouds and the Earth\u2019s Radiant Energy System (CERES): An earth observing system experiment","volume":"77","author":"Wielicki","year":"1996","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"945","DOI":"10.1175\/BAMS-86-7-945","article-title":"The geostationary earth radiation budget project","volume":"86","author":"Harries","year":"2005","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_10","first-page":"1275","article-title":"Description of a complete (interpolated) outgoing longwave radiation dataset","volume":"77","author":"Liebmann","year":"1996","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_11","unstructured":"NOAA Interpolated Outgoing Longwave Radiation (OLR) (2020, January 30). National Oceanic and Atmospheric Administration, Available online: https:\/\/www.esrl.noaa.gov\/psd\/data\/gridded\/data.interp_OLR.html."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2029","DOI":"10.1175\/2007JTECHA989.1","article-title":"Development of the HIRS outgoing longwave radiation climate dataset","volume":"24","author":"Lee","year":"2007","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"389","DOI":"10.1016\/S0034-4257(03)00015-4","article-title":"Outgoing longwave flux estimation: Improvement of angular modelling using spectral information","volume":"85","author":"Clerbaux","year":"2003","journal-title":"Remote Sens. Environ."},{"key":"ref_14","unstructured":"Hersbach, H. (2016). The ERA5 Atmospheric Reanalysis. AGU Fall Meeting Abstracts, American Geophysical Union."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1016\/S0034-4257(97)00084-9","article-title":"Modeling zenith-angle dependence of outgoing longwave radiation: Implication for flux measurements","volume":"62","author":"Otterman","year":"1997","journal-title":"Remote Sens. Environ."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"240","DOI":"10.1175\/1520-0450(2003)042<0240:ADMFTO>2.0.CO;2","article-title":"Angular distribution models for top-of-atmosphere radiative flux estimation from the Clouds and the Earth\u2019s Radiant Energy System instrument on the Tropical Rainfall Measuring Mission satellite. Part I: Methodology","volume":"42","author":"Loeb","year":"2003","journal-title":"J. Appl. Meteorol."},{"key":"ref_17","first-page":"11093","article-title":"Variability of the infrared complex refractive index of African mineral dust: Experimental estimation and implications for radiative transfer and satellite remote sensing","volume":"14","author":"Boucher","year":"2014","journal-title":"Atmos. Chem. Phys. Discuss. Eur. Geosci. Union"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1249","DOI":"10.1175\/JAMC-D-16-0262.1","article-title":"Daytime top-of-the-atmosphere cirrus cloud radiative forcing properties at Singapore","volume":"56","author":"Lolli","year":"2017","journal-title":"J. Appl. Meteorol. Climatol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"3991","DOI":"10.1029\/JD092iD04p03991","article-title":"A cloud type classification with NOAA 7 split-window measurements","volume":"92","author":"Inoue","year":"1987","journal-title":"J. Geophys. Res. Atmos."},{"key":"ref_20","unstructured":"Geier, E., Green, R., Kratz, D., Minnis, P., Miller, W., Nolan, S., and Franklin, C. (2020, January 30). CERES Data Management System: Single Satellite Footprint TOA\/surface Fluxes and Clouds (SSF) Collection Document, Available online: http:\/\/asd-www.larc.nasa.gov\/ceres\/collect_guide\/SSF_CG.pdf."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2125","DOI":"10.1175\/1520-0442(1997)010<2125:RSECTB>2.0.CO;2","article-title":"Removing satellite equatorial crossing time biases from the OLR and HRC datasets","volume":"10","author":"Waliser","year":"1997","journal-title":"J. Clim."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1072","DOI":"10.1175\/JTECH-D-12-00136.1","article-title":"Geostationary enhanced temporal interpolation for CERES flux products","volume":"30","author":"Doelling","year":"2013","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"893","DOI":"10.1175\/2011BAMS3039.1","article-title":"Globally gridded satellite observations for climate studies","volume":"92","author":"Knapp","year":"2011","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Schreck, C.J., Lee, H.T., and Knapp, K.R. (2018). HIRS outgoing longwave radiation\u2014Daily climate data record: Application toward identifying tropical subseasonal variability. Remote Sens., 10.","DOI":"10.3390\/rs10091325"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1990","DOI":"10.1029\/2018MS001364","article-title":"A flexible and efficient radiation scheme for the ECMWF model","volume":"10","author":"Hogan","year":"2018","journal-title":"J. Adv. Model. Earth Syst."},{"key":"ref_26","unstructured":"GCOS (2020, January 30). Systematic Observation Requirements for Satellite-Based Products for Climate (2011 Update): Supplemental Details to the Satellite-Based Component of the \u201cImplementation Plan for the Global Observing System for Climate in Support of the UNFCCC\u201d. Available online: www.wmo.int."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/6\/929\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:06:40Z","timestamp":1760173600000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/12\/6\/929"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,3,13]]},"references-count":26,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2020,3]]}},"alternative-id":["rs12060929"],"URL":"https:\/\/doi.org\/10.3390\/rs12060929","relation":{},"ISSN":["2072-4292"],"issn-type":[{"type":"electronic","value":"2072-4292"}],"subject":[],"published":{"date-parts":[[2020,3,13]]}}}