English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. Cloud liquid water path (LWP) is one of the targetatmospheric parameters retrieved remotely from ground-based and space-borneplatforms using different observation methods and processing algorithms.Validation of LWP retrievals is a complicated task since a cloud cover ischaracterised by strong temporal and spatial variability while remotesensing methods have different temporal and spatial resolutions. An attempthas been made to compare and analyse the collocated LWP data delivered bytwo satellite instruments SEVIRI and AVHRR together with the data derivedfrom microwave observations by the ground-based radiometer RPG-HATPRO.The geographical region of interest is the vicinity of St. Petersburg,Russia, where the RPG-HATPRO radiometer is operating. The study isfocused on two problems. The first one is the so-called scale differenceproblem, which originates from dissimilar spatial resolutions ofmeasurements. The second problem refers to the land–sea LWP gradient. Theradiometric site is located 2.5 km from the coastline where the effects ofthe LWP gradient are pronounced. A good agreement of data obtained at themicrowave radiometer location by all three instruments (HATPRO, SEVIRI, andAVHRR) during warm and cold seasons is demonstrated (the largest correlationcoefficient 0.93 was detected for HATPRO and AVHRR datasets). The analysisshowed no bias of the SEVIRI results with respect to HATPRO data and a largepositive bias (0.013–0.017 kg m −2 ) of the AVHRR results for bothwarm and cold seasons. The analysis of LWP maps plotted on the basis of theSEVIRI and AVHRR measurements over land and water surfaces in the vicinityof St. Petersburg revealed the unexpectedly high LWP values delivered byAVHRR during the cold season over the Neva River bay and over the Saimaa Lakeand the abnormal land–sea LWP gradient in these areas. For the detailedevaluation of atmospheric state and ice cover in the considered geographicalregions during the periods of ground-based and satellite measurements,reanalysis data were used. It is shown that the most probable reason for theobserved artefacts in the AVHRR measurements over water and ice surfaces is thecoarse resolution of the land–sea and snow–ice masks used by the AVHRRretrieval algorithm. The influence of a cloud field inhomogeneity on theagreement between the satellite and the ground-based data is studied. Forthis purpose, the simple estimate of the LWP temporal variability is used asa measure of the spatial inhomogeneity. It has been demonstrated that bothinstruments are equally sensitive to the inhomogeneity of a cloud fielddespite the fact that they have different spatial resolutions.

Cross-comparison of cloud liquid water path derived from observations by two space-borne and one ground-based instrument in northern Europe