{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:27:24Z","timestamp":1760243244802,"version":"build-2065373602"},"reference-count":43,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2014,12,22]],"date-time":"2014-12-22T00:00:00Z","timestamp":1419206400000},"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>Cloud property data sets derived from passive sensors onboard the polar orbiting satellites (such as the NOAA\u2019s Advanced Very High Resolution Radiometer) have global coverage and now span a climatological time period. Synoptic surface observations (SYNOP) are often used to characterize the accuracy of satellite-based cloud cover. Infrequent overpasses of polar orbiting satellites combined with the 3- or 6-h SYNOP frequency lead to collocation time differences of up to 3 h. The associated collocation error degrades the cloud cover performance statistics such as the Hanssen-Kuiper\u2019s discriminant (HK) by up to 45%. Limiting the time difference to 10 min, on the other hand, introduces  a sampling error due to a lower number of corresponding satellite and SYNOP observations. This error depends on both the length of the validated time series and the SYNOP frequency. The trade-off between collocation and sampling error call for an optimum collocation time difference. It however depends on cloud cover characteristics and SYNOP frequency, and cannot be generalized. Instead, a method is presented to reconstruct the unbiased (true) HK from HK affected by the collocation differences, which significantly (t-test p &lt; 0.01) improves the validation results.<\/jats:p>","DOI":"10.3390\/rs61212866","type":"journal-article","created":{"date-parts":[[2014,12,22]],"date-time":"2014-12-22T08:31:01Z","timestamp":1419237061000},"page":"12866-12884","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["The Impact of Time Difference between Satellite Overpass and Ground Observation on Cloud Cover Performance Statistics"],"prefix":"10.3390","volume":"6","author":[{"given":"J\u0119drzej","family":"Bojanowski","sequence":"first","affiliation":[{"name":"Federal Office of Meteorology and Climatology MeteoSwiss, Climate Services, Operation Center 1, P.O. Box 257, CH-8058 Z\u00fcrich-Flughafen, Switzerland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2452-4605","authenticated-orcid":false,"given":"Reto","family":"St\u00f6ckli","sequence":"additional","affiliation":[{"name":"Federal Office of Meteorology and Climatology MeteoSwiss, Climate Services, Operation Center 1, P.O. Box 257, CH-8058 Z\u00fcrich-Flughafen, Switzerland"}]},{"given":"Anke","family":"Tetzlaff","sequence":"additional","affiliation":[{"name":"Federal Office of Meteorology and Climatology MeteoSwiss, Climate Services, Operation Center 1, P.O. Box 257, CH-8058 Z\u00fcrich-Flughafen, Switzerland"}]},{"given":"Heike","family":"Kunz","sequence":"additional","affiliation":[{"name":"Federal Office of Meteorology and Climatology MeteoSwiss, Climate Services, Operation Center 1, P.O. Box 257, CH-8058 Z\u00fcrich-Flughafen, Switzerland"}]}],"member":"1968","published-online":{"date-parts":[[2014,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1175\/JCLI-3243.1","article-title":"Cloud feedbacks in the climate system: A critical review","volume":"18","author":"Stephens","year":"2005","journal-title":"J. Clim."},{"key":"ref_2","unstructured":"Stocker, T.F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V., and Midgley, P.M. (2013). Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press."},{"key":"ref_3","unstructured":"Global Climate Observing System (2010). Implementation Plan for the Global Observing System for Climate in Support of the UNFCCC, Global Climate Observing System. 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