The world’s surface is clustered according to the centennial evolution of near surface temperature, using a continuous piecewise trend methodology applied to the GISS surface temperature data for the last 100 years. A spatial distribution of the timing of onset of local warming, alongside with the local decadal trends are presented and discussed. Time series of temperature, obtained by averaging only regions with the same temperature low frequency behaviour, are also presented and discussed. The world's globe surface is divided into 5 clusters defined by the surface trend temperature behaviour: (1) first and last period of warming having an cooling period in between (59% of the Earth surface), (2) later warming after a continuous cooling period (11% of the Earth surface), (3) later cooling after an initial warming period (9% of the Earth surface), (4) continuous warming (7.5% of the Earth surface) and (5) first and last periods of cooling having an warming period in between (5.4% of the Earth surface).

In the Iberian Peninsula (IP) the rise of temperatures during last decades has been noticeable, especially in spring and summer seasons. The aim of this study is to identify characteristic circulation types (CTs) conducive to the occurrence of warm extremes and to describe long-term changes both in circulation and in the percentage of associated extremes. A sample of 29 long station series of daily maximum (Tmax) and minimum (Tmin) temperature across the IP are considered for the study. Daily mean Sea Level Pressure reconstructions from the EMULATE project for the period 1850-2003 were classified into daily CTs using a simulated annealing clustering technique, separately for spring (MAM) and summer (JJA). The distinct CTs are examined for their tendency to give rise to daily temperature extremes at each specific location. Moreover, the existence of significant trends in the temporal frequency of the CTs is discussed, as well as their within type temporal variations in association to local extremes.

In both seasons, spring and summer, a warming signal has been detected in specific circulation types: especially in spring, an increasing incidence of high pressure conditions in the north of Iberia together with a warming of CTs indicating westerly and south-westerly flows explain the increase in warm days. In summer there is significant long-term positive trend in strong North Atlantic Anticyclone and Iberian thermal low-type patterns, but most of the warming has to be explained by within-type changes: the same CTs give rise to high temperatures more frequently, especially from around the 1970´s.

Short-term exposure to ozone is a public health concern worldwide. Tropospheric ozone is a secondary air pollutant, formed primarily through a complex series of photochemical reactions between nitrogen oxides and reactive hydrocarbons. Hot days with clear skies favour ozone production. Hence a warmer climate is likely to increase ozone ambient concentration and consequently the impact of ozone related health effects.

In this paper we present a statistical model that was developed using an additive mixed modelling approach to estimate daily ozone concentrations based on ground level climate variables, ozone precursors and synoptic atmosphere variables from the National Centre of Environmental Prediction. Two future scenarios (A2a and B2a) of daily ozone concentrations were obtained using the global circulation model (GCM) HadCM3 taking also into account local per capita ozone precursor’s emissions and population growth for each scenario.

This work is focused on the study of the total ozone column (TOC) trends over the Iberian Peninsula during the last 30 years (1979-2009). This analysis is carried out using satellite TOC data and it is divided into two sub-periods in order to detect changes in the ozone trend pattern: from 1979 to 1994 using the NASA Total Ozone Mapping Spectrometer (TOMS) and from 1995 to 2009 by means of the ESA Global Ozone Monitoring Experiment (GOME). The analysis of the long-term ozone trends is performed using annual mean time series derived from the average of the deseasonalized monthly TOC series. The results show that the ozone depletion was statically significant at the 95% confidence level during the first sub-period (1979-1994) in the entire region of study, with linear trends from -4.5 %/decade to -2.9 %/decade. These linear trends presented a clear dependence on latitude, being higher for the Northerner locations than for the Southerner. By contrast, the analysis of the second sub-period of study (1995-2009) presented positive ozone trends from +0.6 %/decade to +1.8 %/decade (only statically significant in four of nine locations of study), indicating that the ozone layer may be responding as expected to the controls on ozone-depleting substances imposed by the Montreal Protocol. Additionally, a seasonal trend analysis is performed using the average of the deseasonalized monthly values for each season of the year. The seasonal analysis showed that while the negative ozone trends during the first sub-period of study were statically significant in the springtime and summertime, the positive seasonal trends during the second sub-period did not show any statistically significance.

Lisbon is the largest urban area in the Western European coast. Due to this geographical position, the Atlantic Ocean is an important source of particles and plays an important role in many atmospheric processes. The main objectives of this work were 1) to perform a chemical characterization of PM_2.5 sampled in Lisbon, 2) to identify the main sources of particles and to determine their contribution to this urban area and 3) to assess the impact of maritime air mass trajectories on the concentration and composition of respirable particles sampled in Lisbon. During 2007, PM_2.5 was collected on a daily basis in the centre of Lisbon with a Partisol sampler. The exposed teflon filters were measured by gravimetry and were cut into two parts: one was analysed by Instrumental Neutron Activation Analysis and the other by Ion Chromatography. Principal Component Analysis and Multilinear Regression Analysis were used to identify possible sources of PM_2.5 and to determine their mass contribution. Five main groups of sources were identified: secondary aerosols, traffic, a source of calcium, soil and sea. Four days backward trajectories, ending in Lisbon, at the starting sampling time were calculated with the Hysplit Model. Results showed that maritime transport scenarios were very frequent. These episodes were characterized by a significant decrease of anthropogenic aerosol concentrations and had a significant role on the air quality from this urban area.

— This project aims at the application of the KLIMA inversion algorithm, optimally suited for CO₂ retrieval and integrated into the ESA GPOD (Grid Processing On-Demand) operational environment, to processing Level-1 data acquired by the IASI instrument onboard the METOP-A satellite and at the retrieval of carbon dioxide columns for comparison and cross-validation with GOSAT TANSO-FTS Level-2 data. The activities included in this study are: the adaptation of the KLIMA algorithm for the retrieval of CO₂ column from IASI spectra; a sensitivity assessment and evaluation of the performances of the optimized KLIMA-IASI code for CO₂ retrieval; the integration of the KLIMA-IASI inversion code on the ESA GRID-based operational environment G-POD (Grid Processing On-Demand); the processing of IASI Level 1 data using the KLIMA-IASI/G-POD retrieval code and a final comparison and cross validation of KLIMA-IASI CO₂ products along with GOSAT/TANSO-FTS operational products. For the performance of the retrieval a target accuracy of 0.3% (1 ppmv out of 370 ppmv) on regional scales (1000 x 1000 km) at monthly intervals was assumed as reference value. The KLIMA-IASI retrieval code integration on G-POD has been completed and is now available for bulk processing of IASI data to be compared with TANSO-FTS measurement products for validation purposes. The consolidated version of the KLIMA-IASI code on G-POD will be then made available to all interested users.