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Abstract. We give an overview of the regional meteorological situation during the Indian Ocean Experiment INDOEX intensive field phase (IFP) in February andMarch 1999. The INDOEX domain, reaching from 30øN to 30øS and from 50øE to 100øE, was chosen because the low-level outflow of pollution from India is carried by the northeasterly trades into the tropical convergence zone, where cloud processing modifies the properties of the aerosols. In contrast, there is also an inflow of pristine southern hemispheric air by the southeasterly trades into the convergence zone. However, during the 1999 IFP some deviations from the climatological mean were observed. In 1999 the Intertropical Convergence Zone (ITCZ) was broken into a northern convergence zone and a southern convergence zone. During February the northern zone was more active and the cross-equatorial flow (N-->S) was weak, both suggesting that less pollution was transported to the southern hemisphere. In

[1] A European average temperature with monthly resolution is constructed based on the E-OBS daily data set with near real-time updates for monitoring. Taken together, the European average temperature and the associated gridded daily maps of surface temperature from the E-OBS data set provide a detailed record of European climate variability and change since 1950. Both are based on validated station data provided by the European National Meteorological and Hydrological Services. A quantitative analysis of the uncertainty sources to the European average temperature indicates that the uncertainties due to urbanization, statistical interpolation, and the potential inhomogeneities in the input records to E-OBS dominate the total uncertainty estimate. In the aggregation of the interpolation uncertainty from the daily to the monthly level and then to a European averaged value, the effective sample size and the effective spatial degrees of freedom are estimated to account for spatial and temporal coherency in the uncertainty estimates. The European average temperature shows that 7 years of the top 10 warmest years are from the period starting as recent as the year 2000 and a clear upward trend in annual average temperatures over the last few decades is visible. The most recent year in the top 10 coldest years is 1987. It also shows that warming in Europe is accelerating compared to the warming over the global land masses and to a lesser extent compared to the Northern Hemisphere land masses over the period 1980-2010.

During the TC4 (Tropical Composition, Clouds, and Climate Coupling) campaign in July–August 2007, daily ozonesondes were launched over coastal Las Tablas, Panamá (7.8°N, 80°W) and several times per week at Alajuela, Costa Rica (10°N, 84°W). Wave activity, detected most prominently in 100–300 m thick ozone laminae in the tropical tropopause layer, occurred in 50% (Las Tablas) and 40% (Alajuela) of the soundings. These layers, associated with vertical displacements and classified as gravity waves (GW, possibly Kelvin waves) by laminar identification, occur with similar structure and frequency over the Paramaribo (5.8°N, 55°W) and San Cristóbal (0.92°S, 90°W) Southern Hemisphere Additional Ozonesondes (SHADOZ) sites. GW‐labeled laminae in individual soundings correspond to cloud outflow as indicated by DC‐8 tracers and other aircraft data, confirming convective initiation of equatorial waves. Layers representing quasi‐horizontal displacements, referred to as Rossby waves by the laminar technique, are robust features in soundings from 23 July to 5 August. The features associated with Rossby waves correspond to extratropical influence, possibly stratospheric, and sometimes to pollution transport. Comparison of Las Tablas and Alajuela ozone budgets with 1999–2007 Paramaribo and San Cristóbal soundings shows that TC4 is typical of climatology for the equatorial Americas. Overall during TC4, convection and associated waves appear to dominate ozone transport in the tropical tropopause layer; intrusions from the extratropics occur throughout the free troposphere.

Abstract. We present the seasonal cycle of optical and physical particle properties over the Indian Ocean based on case studies of six-wavelength aerosol lidar observations performed in the framework of the Indian Ocean Experiment. From