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The increasing global demand for food will be met chiefly by increased intensification of production. For crops, this will be achieved largely by increased yields per area with a smaller contribution from an increased number of crops grown in a seasonal cycle. Production systems show a spectrum of intensification practices characterised by varying methods of site preparation and pest control, and
Assessments of the possible future climate change, driven by anthropogenic emissions of greenhouse gases, are made with global climate models. These describe the large-scale features rather than regional details of climate, such as variations due to mountains, lakes, and inland oceans. Regional climate modelling improves the details in climate projections. Examples for the Nordic region illustrate
Four downscaling experiments of regional climate change for the Nordic countries have been conducted with three different regional climate models (RCMs). A short synthesis of the outcome of the suite of experiments is presented as an ensemble, reflecting the different driving atmosphere-ocean general circulation model (AOGCM) conditions, RCM model resolution and domain size, and choice of emission
The Swedish regional climate modelling programme, SWECLIM, started in 1997 with the main goal being to produce regional climate change scenarios over the Nordic area on a time scale of 50 to 100 yr. An additional goal is to produce water resources scenarios with a focus on hydropower production, dam safety, water supply and environmental aspects of water resources. The scenarios are produced by a
Two 2 x 10-year climate change experiments made with the Rossby Centre regional Atmospheric climate model (RCA) are reported. These two experiments are driven by boundary data from two global climate change simulations, one made with HadCM2 and the other with ECHAM4/OPYC3, in which the global mean warning is virtually the same, 2.6°C. The changes in mean temperature and precipitation show similari
This work presents a regional climate model, the Rossby Centre regional Atmospheric model (RCA1), recently developed from the High Resolution Limited Area Model (HIRLAM). The changes in the HIRLAM parametrizations, necessary for climate-length integrations, are described. A regional Baltic Sea ocean model and a modeling system for the Nordic inland lake systems have been coupled with RCA1. The cou
The paper presents a new global modeling tool, Stratospheric Chemical Transport Model 2. It has been developed for effective three-dimensional multiyear stratospheric chemistry studies, featuring an extensive chemistry scheme, heterogeneous processing on sulfate aerosols, and some polar stratospheric cloud processes. The transport algorithm maintains sub-grid-scale distributions and connects verti
The chemically induced ozone loss inside the Arctic vortex during the winter 1994/95 has been quantified by coordinated launches of over 1000 ozonesondes from 35 stations within the Match 94/95 campaign. Trajectory calculations, which allow diabatic heating or cooling, were used to trigger the balloon launches so that the ozone concentrations in a large number of air parcels are each measured twic
The total ozone reduction in the Arctic during the winters of 1993/94 acid 1994/95 has been evaluated using the ground-based total ozone measurements of five SAOZ spectrometers distributed in the Arctic and from number density profiles of a balloon-borne version of the instrument. The ozone change resulting from transport has been removed using a 3D Chemistry Transport Model (CTM) run without chem
Polar stratospheric clouds (PSC) were observed with the multi-wavelength lidar of the MOANA project (Modelling and Observations of Aerosols in the Northern Atmosphere) during SESAME (Second European Stratospheric Arctic and Mid-latitude Experiment). The physical state, liquid or solid, of the cloud particles can be inferred from the lidar data. Using isentropic back-trajectories to obtain the ther
A Lagrangian approach has been used to assess the degree of chemically induced ozone loss in the Arctic lower stratosphere in winter 1991/1992. Trajectory calculations are used to identify air parcels probed by two ozonesondes at different points along the trajectories. A statistical analysis of the measured differences in ozone mixing ratio and the time the air parcel spent in sunlight between th
The absence of LIDAR depolarization in a polar cirrus observed above Sodankyla (Finland) showed the presence of spherical particles at -65°C. The presence of pure liquid water is excluded, since homogeneous freezing should occur at or above -40°C. The cirrus layer was detected at the tropopause, during the horizontal and vertical advection above northern Scandinavia of warm and wet oceanic air. Tw
Balloon borne frost-point hygrometers and backscatter sondes were launched at Sodankylä, Finland in January and February of 1996. These instruments measure water vapor and the backscatter ratio of light due to polar stratospheric clouds in the Arctic stratospheric vortex. Here we report the results of a hygrometer sonde and a backscatter sonde launched within 3.5 hours of each other on January 22/
It is well established that extensive depletion of ozone, initiated by heterogenous reactions on polar stratospheric clouds (PSCs) can occur in both the Arctic and Antarctic lower stratosphere. Moreover, it has been shown that ozone loss rates in the Arctic region in recent years reached values comparable to those over the Antarctic. But until now the accumulated ozone losses over the Arctic have
A Finnish national climate research programme, SILMU, has funded three projects in the field of ozone and UV radiation research during 1990-1995. The results of these projects are summarised here. The study of temperature sounding records made in Finland 1958-94 has revealed a warming trend in the lower and middle troposphere (up to 0.3 K/decade) and a cooling of similar order of magnitude in the
Measurements of tropospheric ozone at three sites at the Arctic Circle in the Finnish Lapland are presented. The variability of ground-level ozone over the diurnal and seasonal cycles in 1992-93 is discussed for the sites of Oulanka and Pallas. The variability with height and over the annual cycle in 1989-94 is discussed for the Sodankyla aerological Observatory, which has the longest record on th
LONG-TERM depletion of ozone has been observed since the early 1980s in the Antarctic polar vortex, and more recently at mid-latitudes in both hemispheres, with most of the ozone loss occurring in the lower stratosphere1. Insufficient measurements of ozone exist, however, to determine decadal trends in ozone concentration in the Arctic winter. Several studies of ozone concentrations in the Arctic
In this study we address the question of temporal ozone trends on isentropic surfaces within the Arctic polar vortex during EASOE. We have combined ozone sonde data from twelve campaign stations distributed throughout the European sector of the Arctic. The development of ozone at the 425, 475, 550 and 700K levels is presented, using analysed fields of isentropic potential vorticity and isentropic
This special issue of Climatic Change contains a series of research articles documenting co-ordinated work carried out within a 3-year European Union project 'Prediction of Regional scenarios and Uncertainties for Defining European Climate change risks and Effects' (PRUDENCE). The main objective of the PRUDENCE project was to provide high resolution climate change scenarios for Europe at the end o
The Swedish Regional Climate Modelling Programme, SWECLIM, was a 6.5-year national research network for regional climate modeling, regional climate change projections and hydrological impact assessment and information to a wide range of stakeholders. Most of the program activities focussed on the regional climate system of Northern Europe. This led to the establishment of an advanced, coupled atmo
