AVHRR warm‐season cloud climatologies under various synoptic regimes across the Iberian Peninsula and the Balearic Islands

Abstract

In this study we retrieved the spatial distribution of mid‐afternoon clouds under various synoptic regimes across the Iberian Peninsula and the Balearic Islands for the warm/convective‐season, from May to October. Accurate daily cloud masks were derived by applying a daytime over land multispectral convective cloud detection algorithm spanning 15 years (1997–2011) of Advanced Very High Resolution Radiometer (AVHRR) HRPT data. We processed a total of 2094 afternoon overpasses (between 1230 and 1720 UTC) corresponding to the NOAA‐14, NOAA‐16 and NOAA‐18 spacecrafts, and stratified daily cloud masks as a function of: (1) the automated circulation‐typing scheme of Jenkinson and Collinson and (2) the prevailing wind field at 850 hPa. The AVHRR warm‐season cloud climatology with high spatial resolution (1.1‐km) identified six representative areas (regions of interest; ROIs) with intensified cloud activity (hot spots). The results also revealed the typical spatial distribution of clouds for each synoptic regime across the whole region, identified the synoptic patterns and wind regimes under which high amounts of clouds occur for each ROIs, and showed that strong boundary layer winds in general increase the frequency of clouds. The regional cloud climatology presented here could be useful, e.g. to improve convective short‐term forecasting by identifying active cloud areas for each atmospheric type.

Green LAI Mapping and Cloud Gap-Filling Using Gaussian Process Regression in Google Earth Engine

“…This is the purpose of image (e) in Figure 8 , which provide a zoom of the LAI G map of 30 June over the so-called Atlantic Mountain Range and the Pyrenees. This subset area represents a critical test site, being characterized by a severe cloud presence (probability between 60% and 70% between April and October [ 59 ]). Again, no radiometric discontinuities or artifacts can be detected both in coastal and mountainous zones, confirming the high reliability of the kernel-based gap-filling regression method we proposed over multi-tiled areas of study.…”

Trends of daily peak wind gusts in Spain and Portugal, 1961–2014

“…Our secondary objective focused on investigating the possible impact of the North Atlantic Oscillation index and the Jenkinson and Collison weather‐typing classification on the observed variability of DPWG. Over this midlatitude region, the majority of extreme wind gust episodes are associated with extratropical cyclones during the cold season (November–April) [ Font‐Tullot , ] and with deep mesoscale thunderstorms (e.g., downbursts and rare tornadic activity) during the warm season (May–October) [ Azorin‐Molina et al ., ]. The complex topography of the IP also enhances the occurrence of severe damage wind events [ Ayala‐Carcedo and Olcina‐Cantos , ], particularly in high mountainous summits and also on densely populated coastal areas [ Martin‐Vide and Olcina‐Cantos , ].…”

Regional high‐resolution cloud climatology based on MODIS cloud detection data

“…Regional cloud climatologies have been developed over a number of locations worldwide, including: the Mediterranean Sea (Levizzani et al, 2010), the Baltic Sea (Rastoskuyev and Shalina, 1996), the North Sea (Berger, 1995), the Central Arctic Ocean (Lubin and Morrow, 1998), the Canary Islands (González et al, 2007), Scandinavia (Karlsson, 2003;Karlsson et al, 2008), the Alps (Kästner and Kriebel, 2001), the Tatra Mountains, (Kotarba, 2010b), Denmark (Jorgensen, 2000), the Upper Rhine Valley (Heinzmann, 1993), the Upper Indus Basin (Forsythe et al, 2015), the Great Lakes (Ackerman et al, 2013), the Iberian Peninsula (Azorin-Molina et al, 2015), the Mackenzie Basin in the Arctic (Garand and Nadon, 1998), the Arctic (Key and Barry, 1989), East Antarctica (Murata and Yamanouchi, 1997), and the South Pole (Lubin and Harper, 1996), amongst many others.…”