Climatic Variability in the Kuparuk Region, North-central Alaska: Optimizing Spatial and Temporal Interpolation in a Sparse Observation Network

Air temperature fields are required as input to spatial models in ecology, geocryology, and biogeochemistry. Air temperature data from a sparse, irregular meteorological network in the Kuparuk region of north-central Alaska were interpolated spatially and temporally to provide a 13-year (1987-1999) series of thawing degree-day fields at 1 km² resolution. Procedures involved standardizing diverse temperature records and applying topographically and climatologically aided interpolation, using station data and digital elevation models, to incorporate the effects of local topography. The accuracy of the interpolation procedures was assessed using cross validation. Considering the number of data points used for interpolation, their distribution, and the size of the area, the combination of climatologically assisted and topographically informed spatial interpolation procedures provides adequate representation of the annual degree-day fields for the Kuparuk region. Spatially integrated mean absolute error does not exceed 3% in any year. To investigate the spatial distribution of interpolation uncertainties, the cross-validation errors obtained at each station for each year were interpolated spatially to a regular 1 × 1 km grid consistent with the degree-day fields.Des champs de température de l'air sont nécessaires en tant que données en entrée pour les modèles spatiaux en écologie, géocryologie et biogéochimie. On a fait des interpolations spatiales et temporelles de données de température de l'air provenant d'un réseau météorologique épars et irrégulier situé dans la région de Kuparuk, au centre-nord de l'Alaska, afin d'obtenir sur 13 ans (1987-1999) une série de champs de degrés-jours de dégel à une résolution de 1 km². On a dû normaliser les divers enregistrements de température et appliquer l'interpolation assistée sur les plans topographique et climatologique, en recourant aux données des stations et à des modèles altimétriques numériques qui intègrent les effets de la topographie locale. La précision des procédures d'interpolation a été évaluée par validation croisée. Compte tenu du nombre de points de données qui ont servi à l'interpolation, de leur distribution ainsi que de l'étendue de la zone, la combinaison des procédures d'interpolation spatiale assistées sur le plan du climat et fondées sur la topographie offre une représentation adéquate des champs de degrés-jours annuels pour la région de Kuparuk. Pour chaque année, l'écart moyen intégré spatialement ne dépasse pas 3 %. Pour étudier la distribution spatiale des incertitudes d'interpolation, les erreurs de validation croisée obtenues à chaque station et pour chaque année ont été interpolées spatialement à une grille normale de 1 × 1 km qui concorde avec les champs de degrés-jours

Summary and outstanding scientific challenges for research of environmental changes in Siberia

This chapter summarizes the volume content focusing on land change in Siberia. The volume is compilation of results of the most recent international studies of Earth's system interactions including biogeochemical and water cycles, natural ecosystems changes, and human impacts on environment. Outstanding scientific challenges are outlined as they were discussed in each chapter

Flood risk and climate change: global and regional perspectives

A holistic perspective on changing rainfall-driven flood risk is provided for the late 20th and early 21st centuries. Economic losses from floods have greatly increased, principally driven by the expanding exposure of assets at risk. It has not been possible to attribute rain-generated peak streamflow trends to anthropogenic climate change over the past several decades. Projected increases in the frequency and intensity of heavy rainfall, based on climate models, should contribute to increases in precipitation-generated local flooding (e.g. flash flooding and urban flooding). This article assesses the literature included in the IPCC SREX report and new literature published since, and includes an assessment of changes in flood risk in seven of the regions considered in the recent IPCC SREX report—Africa, Asia, Central and South America, Europe, North America, Oceania and Polar regions. Also considering newer publications, this article is consistent with the recent IPCC SREX assessment finding that the impacts of climate change on flood characteristics are highly sensitive to the detailed nature of those changes and that presently we have only low confidence1 in numerical projections of changes in flood magnitude or frequency resulting from climate change

State of the Climate in 2012

International audienceEditors note: For easy download the posted pdf of the State of the Climate for 2012 is a very low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download