Remote sensing of alpine glaciers in visible and infrared wavelengths: a survey of advances and prospects

Remote sensing is an efficient tool for temporal monitoring of inaccessible alpine glacial terrain. This study discusses the methods of remote sensing in visible and infrared (IR) wavelengths, which are helpful in providing important information about alpine glaciers. The scope of this study covers recent advances and prospects in optical and thermal remote sensing of glacier facies, glacier velocity, mass balance, glacial hazards and automated mapping techniques. The technology is ever evolving with the advent of new remote sensors capturing data in visible/IR wavelengths and better digital computing technology. An extensive list of significant studies further helps the reader to explore a particular topic of interest. We survey recent advances in this field and additionally highlight the emerging prospects.     

Coarse-Scale Horizontal Distribution of Phytoplankton in a Semi-Enclosed Coastal Area

Abstract. The horizontal distribution of phytoplankton in relation to changes in the physico-chemical conditions of a eutrophic semi-enclosed embayment is described. Phytoplanktonic populations derived from a station interval of 6 miles (coarse scale variations) were compared by quantitative (standing stock) and qualitative (species composition, diversity, Diatom/Flagellate ratio) criteria. The results showed that quantitative and qualitative parameters differed in their sensitivity and were affected differently by environmental perturbations. Along a horizontal transect with defined variations in nutrient concentrations, changes in standing stock levels were not significant, but differences in species composition existed and caused coefficients of variation between stations for species diversity up to 50% and of the Diatom/Flagellate ratio up to 120%. Furthermore, distributional differences among certain flagellate species (Prorocentrum micans, Prorocentrum balticum) and diatom species (Nitzschia closterium, Chaetoceros curvisetus) were recorded which showed that the flagellate species were distributed more uniformly than the diatoms along a transect with progressive decrease in nutrient concentrations.     

VARIABILITY OF DAILY PRECIPITATION IN CHINA(1980-1993):PCA AND WAVELET ANALYSIS OF OBSERVATION AND ECMWF REANALYSIS DATA

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Assessing adaptive capacity within regional climate change vulnerability studies—an Alpine example

Adaptive capacity represents a crucial component in the assessment of a region’s vulnerability to climate change. The term adaptive capacity is only fuzzily defined, and determining it is difficult and often neglected in previous studies. In this paper, a newly developed adaptive capacity concept is introduced, with a respective indicator/criteria system and simple aggregation methods. The approach allows for adaptive capacity assessments at 3 levels of specificity (impact specific, sector specific and regional generic). The selection of indicators is tailor-made for Alpine regions, where the approach has been widely tested. The presented approach requires extended stakeholder involvement, namely for the evaluation of the indicators. The overall effort needed for its implementation remains reasonable. The outcome of the assessment exercise does not provide precise objective measurements, but remains an indicative estimation due to the fuzziness and complexity of the underlying concept. The conceptual approach is transferable to other mountain areas and beyond, the selection of indicators however is only valid for the Alpine region. The showcase presents results from the adaptive capacity assessment in the region of South Tyrol, where the method was carried out as part of a climate change vulnerability study. The outcomes indicate a number of issues that future actions could address in order to improve adaptive capacity in the region, namely in the field of prevention measures against meteorological extremes and natural hazards.     

Fission‐track dating of a tephra layer related to Poti‐Malal and Seguro drifts in the Río Grande basin,Mendoza, Argentina

Two old drift units called Poti‐Malal and Seguro have been differentiated in the Río Grande basin based on relative‐age criteria, stratigraphical relationships, morphology and fission‐track dating. A tephra dated at 0.226 ± 0.025 Ma was deposited on the Poti‐Malal drift and underlies the Seguro outwash, which is inferred to equate with marine oxygen isotope stage 6. The stratigraphical position and age suggest that the tephra post‐dates the Poti‐Malal glaciation and that it is older than the Seguro drift. The Poti‐Malal glaciation must be at least as old as Early–Middle Pleistocene, and the Seguro glaciation is assigned to the penultimate glaciation. The tephra unit may have been deposited during marine oxygen isotope stage 7. Copyright © 2002 John Wiley & Sons, Ltd.     

Using geostatistical simulation to disaggregate air quality model results for individual exposure estimation on GPS tracks

In this work, we address the mismatch in spatio-temporal resolution between individual, point-location based exposure and grid cell based air quality model predictions by disaggregating the grid model results. Variability of PM₁₀ point measurements was modelled within each grid cell by the exponential variogram, using point support concentration measurements. Variogram parameters were estimated over the study area globally using constant estimates, and locally by multiple regression models using traffic, weather and land use data. Model predictions of spatio-temporal variability were used for geostatistical unconditional simulation, estimating the deviation of point values from grid cell averages on GPS tracks. The distribution of deviations can be used as an estimate of uncertainty for individual exposure. Results showed a relevant impact of the disaggregation uncertainties compared to other uncertainty sources, dependent of the model used for spatio-temporal variability. Depending on individual behaviour and variability of the pollutant, these uncertainties average out again over time.     

Modelling Indonesian rainfall with a coupled regional model

Long-term high-resolution coupled climate model simulations using the Max Planck Institute Regional Climate Model and the Max Planck Institute Ocean Model have been performed with boundary forcings from two reanalyses: firstly from the European Centre for Medium-Range Weather Forecasts, and secondly from the joint reanalysis of the National Centers for Environmental Prediction and the National Center for Atmospheric Research. This study employs a special coupling setup using a regional atmospheric model and a global ocean model. The latter model applies a special conformal grid from a bipolar orthogonal spherical coordinate system, which allows irregular positions of the poles and focuses on the detail over the Maritime Continent. The coupled model was able to simulate stable and realistic rainfall variabilities without flux correction and at two different ocean resolutions. The coupled system is integrated for a period between 1979 and 1993 and the results are then compared to those from uncoupled runs and from observation. The results show improved performance after coupling: a remarkable reduction of overestimated rainfall over the sea for the atmospheric model and of warm SST biases for the ocean model. There is no significant change in rainfall variability at higher ocean model resolution, but the ocean circulation shows less transport variability within the Makassar Strait in comparison to observations. This paper has not been published or considered by any other journal in any language.     

A chronological and palaeoenvironmental re-evaluation of two loess-palaeosol records in the northern Harz foreland,Germany, based on innovative modelling tools

The continuing development of analytical methods for investigating sedimentary records calls for iterative re-examination of existing data sets obtained on loess-palaeosol sequences (LPS) as archives of palaeoenvironmental change. Here, we re-investigate two LPS (Hecklingen, Zilly) in the northern Harz foreland, Germany, being of interest due to their proximity to the Scandinavian Ice Sheet (SIS) and the position between oceanic climatic influence further west and continental influence towards the east. First, we established new quartz OSL and polymineral IRSL chronologies. Both methods show concordant ages in the upper part of the Hecklingen profile (~20–40 ka), but in the lower part IRSL underestimates OSL ages by up to ~15 ka for the period 40–60 ka. Interpretations hence refer to the OSL data set. Second, we applied Bayesian age-depth modelling to data sets from Hecklingen to resolve inversions in the original ages, also reducing averaged 1σ uncertainty by ~19% (OSL) and ~12% (IRSL). Modelled chronologies point out phases of increased (MIS 2, early MIS 3) and reduced (middle and late MIS 3) sedimentation, but interpretation of numerical rates is problematic because of intense erosion and slope wash particularly during MIS 3. Finally, previously obtained grain-size data were re-investigated by end member modelling analyses. Three fundamental grain-size distributions (loadings) explain the measured data sets and offer information on intensity and – combined with modelled OSL ages – timing of geomorphic processes. We interpret the loadings to represent (i) primary loess accumulation, (ii) postdepositional pedogenesis and/or input of aeolian fine fractions, and (iii) input of coarse aeolian material and/or slope wash. The applied modelling tools facilitate detailed understanding of site-formation through time, allowing us to correlate a strong peak in mean grain size at ~26–24 ka to the maximum extent of the SIS and increased influence of easterly winds.