The sulphate component in aerosol samples over the North Atlantic

The size distribution of sulphate containing particles over the North Atlantic was determined for particles with radii larger than 0.18 µm. It is compared with the size distributions of the total aerosol, the hygroscopic and the insoluble parts in the maritime aerosol. From mass concentrations of sulphate and sodium, it can be concluded that only a fraction of sulphate originates from the ocean. The sulphate mass distribution separated into its sea salt sulphate and excess sulphate components is compared with a continental distribution

The sulphate component in aerosol samples over the Noth Atlantic Ocean (Tab. 1)

The size distribution of sulphate containing particles over the North Atlantic was determined for particles with radii larger than 0.18 µm. It is compared with the size distributions of the total aerosol, the hygroscopic and the insoluble parts in the maritime aerosol. From mass concentrations of sulphate and sodium, it can be concluded that only a fraction of sulphate originates from the ocean. The sulphate mass distribution separated into its sea salt sulphate and excess sulphate components is compared with a continental distribution

Konzentrationsverhältnisse von Aerosolkomponenten über dem Nordatlantik

Aerosol samples collected over the North Atlantic from ship were analysed for Sodium, Magnesium, Potassium, Calcium and Chloride. A found dependence of sea salt concentrations from wind velocity is compared with earlier results. The mean of the ratio Cl/Na was close to that for sea water; the Mg-, K- and Ca-concentrations in the aerosol, however, were enriched with respect to sea water. It is shown that continental advection influences the measured aerosol components over the North Atlantic

Concentration of aerosol components over the Noth Atlantic Ocean (Tab. 2)

Aerosol samples collected over the North Atlantic from ship were analysed for Sodium, Magnesium, Potassium, Calcium and Chloride. A found dependence of sea salt concentrations from wind velocity is compared with earlier results. The mean of the ratio Cl/Na was close to that for sea water; the Mg-, K- and Ca-concentrations in the aerosol, however, were enriched with respect to sea water. It is shown that continental advection influences the measured aerosol components over the North Atlantic

Numerical analysis of flux footprints for different landscapes

A model for the canopy - planetary boundary layer flow and scalar transport based on E-is an element of closure was applied to estimate footprint for CO2 fluxes over different inhomogeneous landscapes. Hypothetical heterogeneous vegetation patterns - forest with clear-cuts as well as hypothetical heterogeneous relief - a bell-shaped valley and a ridge covered by forest were considered. The distortions of airflow caused by these heterogeneities are shown - the upwind deceleration of the flow at the ridge foot and above valley, acceleration at the crest and the flow separation with the reversed flow pattern at lee slopes of ridge and valley. The disturbances induce changes in scalar flux fields within the atmospheric surface layer comparing to fluxes for homogeneous conditions: at a fixed height the fluxes vary as a function of distance to disturbance. Correspondingly, the flux footprint estimated from model data depends oil the location of the point of interest (flux measurement point) and may significantly deviate from that for a flat terrain. It is shown that proposed method could be used for the choice of optimal sensor position for flux measurements over complex terrain as well as for the interpretation of data for existing measurement sites. To illustrate the latter the method was applied for experimental site in Selling, Germany, taking into account the complex topography and vegetation heterogeneities. Results show that in certain situations (summer, neutral stratification, south or north wind) and for a certain sensor location the assumptions of idealized air flow structure could be used for measurement interpretation at this site, though in general, extreme caution should be applied when analytical footprint models are used in the interpretation of flux measurements over complex sites

Measured daily precipitation sums over Central Sulawesi for the period 1981-1999

Data compiled within the IMPENSO project. The Impact of ENSO on Sustainable Water Management and the Decision-Making Community at a Rainforest Margin in Indonesia (IMPENSO), http://www.gwdg.de/~impenso, was a German-Indonesian research project (2003-2007) that has studied the impact of ENSO (El Nino-Southern Oscillation) on the water resources and the agricultural production in the PALU RIVER watershed in Central Sulawesi. ENSO is a climate variability that causes serious droughts in Indonesia and other countries of South-East Asia. The last ENSO event occurred in 1997. As in other regions, many farmers in Central Sulawesi suffered from reduced crop yields and lost their livestock. A better prediction of ENSO and the development of coping strategies would help local communities mitigate the impact of ENSO on rural livelihoods and food security. The IMPENSO project deals with the impact of the climate variability ENSO (El Niño Southern Oscillation) on water resource management and the local communities in the Palu River watershed of Central Sulawesi, Indonesia. The project consists of three interrelated sub-projects, which study the local and regional manifestation of ENSO using the Regional Climate Models REMO and GESIMA (Sub-project A), quantify the impact of ENSO on the availability of water for agriculture and other uses, using the distributed hydrological model WaSiM-ETH (Sub-project B), and analyze the socio-economic impact and the policy implications of ENSO on the basis of a production function analysis, a household vulnerability analysis, and a linear programming model (Sub-project C). The models used in the three sub-projects will be integrated to simulate joint scenarios that are defined in collaboration with local stakeholders and are relevant for the design of coping strategies

IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 39, NO. 2, FEBRUARY 2001 241 The Role of Canopy Structure in the Spectral

This paper presents empirical and theoretical analyses of spectral hemispherical reflectances and transmittances of individual leaves and the entire canopy sampled at two sites representative of equatorial rainforests and temperate coniferous forests. The empirical analysis indicates that some simple algebraic combinations of leaf and canopy spectral transmittances and reflectances eliminate their dependencies on wavelength through the specification of two canopy-specific wavelength-independent variables. These variables and leaf optical properties govern the energy conservation in vegetation canopies at any given wavelength of the solar spectrum. The presented theoretical development indicates these canopy-specific wavelength-independent variables characterize the capacity of the canopy to intercept and transmit solar radiation under two extreme situations, namely, when individual leaves 1) are completely absorptive and 2) totally reflect and/or transmit the incident radiation. The interactions of photons with the canopy at red and near-infrared (IR) spectral bands approximate these extreme situations well. One can treat the vegetation canopy as a dynamical system and the canopy spectral interception and transmission as dynamical variables. The system has two independent states: canopies with totally absorbing and totally scattering leaves. Intermediate states are a superposition of these pure states. Such an interpretation provides powerful means to accurately specify changes in canopy structure both from ground-based measurements and remotely sensed data. This concept underlies the operational algorithm of global leaf area index (LAI), and the fraction of photosynthetically active radiation absorbed by vegetation developed for the moderate resolution imaging spectror..