No abstract

Variations of the global sea level pressure (SLP) field reflect atmospheric and oceanic influences and have a profound influence on temperature, precipitation and the global carbon cycle. The impact of various forcing factors on this field was investigated mainly based on numerical simulations. Alternatively, here we identify and quantify the influences of various forcing factors on observational, reanalysis and simulated SLP fields. By applying canonical correlation analysis (CCA) on the aforementioned data sets, we separated and quantified the impact of increase CO 2 concentration, El Niño-Southern Oscillation (ENSO), Atlantic Multidecadal Oscillation (AMO), Arctic Oscillation (AO) and solar forcing on the global SLP field, based on their associations with known footprints on the sea surface temperature (SST). Together, their corresponding SLP spatial structures explain ~ 60% of the observed variance. Whereas the atmospheric CO 2 concentration has the most prominent impact on the global SLP field, explaining 28% of variance, ENSO and AO account for 9% each. The solar forcing and AMO explain 7%, respectively 6% of global SLP variance. Similar spatial structures corresponding to the same forcing factors are identified based on the reanalysis SLP data. CCA applied on simulated SLP fields derived from six CMIP5 model simulations captures only the spatial structures of atmospheric CO 2 concentration, ENSO, AAO and AO. Such a decomposition of the global pressure field based on a linear combination of coupled SST-SLP pairs provide a reference against which one could validate the performance of general circulation models in simulating the lower atmosphere dynamics. KeywordsSea level pressure • Ocean temperature • CO 2 • Internal modes of variability • Solar influence Electronic supplementary material The online version of this article (

Data collected over a period of 18 months (December 2019–May 2021) at the Bucharest–Măgurele Cloudnet station were analysed for the first time to determine the macrophysical and microphysical cloud properties over this site. A total number of 1,327,680 vertical profiles containing the target classification based on the Cloudnet algorithm were analysed, of which 1,077,858 profiles contained hydrometeors. The highest number of profiles with hydrometeors (>60%) was recorded in December 2020, with hydrometeors being observed mainly below 5 km. Above 5 km, the frequency of occurrence of hydrometeors was less than <20%. Based on the initial Cloudnet target classification, a cloud classification scheme was implemented. Clouds were more frequently observed during winter compared with other seasons (45% of all profiles). Ice clouds were the most frequent type of cloud (468,463 profiles) during the study period, followed by mixed phases (220,280 profiles) and mixed phased precipitable clouds (164,868 profiles). The geometrical thickness varied from a median value of 244 m for liquid clouds during summer to 3362 m for mix phased precipitable clouds during spring.

&lt;p&gt;In the framework of the Joint Aeolus Tropical Atlantic Campaign (JATAC), the ASKOS experiment was implemented in Cabo Verde during summer and autumn of 2021 and 2022. The main objective of ASKOS was the collection of an unprecedented dataset of synergistic measurements in the region, to be used to address a wide range of scientific objectives, namely the support of the validation of Aeolus mission&amp;#8217;s products, the study of the processes affecting dessert dust transport (water vapor, giant particles, mixing with boundary layer dynamics), the characterization of the cloud microphysics, the effect of dust particles in the cloud formation over the region, the effect of the large dust particles on radiation and others.&lt;/p&gt; &lt;p&gt;During the ASKOS experiment, intense ground-based remote sensing and airborne in situ measurements took place on and above Mindelo on the island of S&amp;#227;o Vicente, Cabo Verde. At the Ocean Science Center in Mindelo (OSCM), a full ACTRIS remote sensing super site was set up in 2021, including a multiwavelength-Raman-polarization lidar PollyXT, an AERONET sun photometer, a Scanning Doppler wind lidar, a microwave radiometer and a cloud radar belonging to ESA fiducial reference network (FRM4Radar). Additionally, the ESA&amp;#8217;s reference lidar system eVe, a combined linear/circular polarization lidar with Raman capabilities, was deployed. In 2022, the operations were enhanced with the deployment of airborne in-situ aerosol measurements on-board UAVs deployed by the Cyprus Institute, solar radiation measurements supported by PMOD/WRC, dust particle orientation measurements from the WALL-E lidar of National Observatory of Athens, and radiosonde releases equipped with additional electric field and electric charge measurements. The campaign was supported by dedicated numerical weather and dust simulations from CAMS and ECMWF, and tailored WRF simulations with nested domains above the campaign site. &amp;#160;&lt;/p&gt; &lt;p&gt;From the ASKOS dataset, three cases have been selected as &quot;golden cases&amp;#8221; where multiple JATAC airborne platforms and Aeolus satellite performed collocated measurements alongside with the ground-based instrumentation around the ASKOS operations site. Furthermore, multiple synergistic measurements with the JATAC airborne platforms were performed in the broader Cabo Verde region. Here, we quickly introduce ASKOS measurements and present first results.&amp;#160;&lt;/p&gt;