NHF large prize

Since 1990 NHF has awarded the so-called “large prize” to the author(s) of the best paper in Hydrology Research/Nordic Hydrology originating from one of the Nordic/Baltic countries and published in the journal in one of the previous two full years.

The prize for 2010 was awarded to Asgeir Petersen-Øverleir for the contribution

   Fitting depth-discharge relationships in rivers with floodplains
   Hydrology Research, Vol. 39, No. 5-6, 369-384, 2008

The paper takes us back to the roots of hydrology. Without reliable measurements in the field there would be no hydrology. Theoretically-based data processing is an inherent part of this effort. The author has developed a method for reliable estimation of the flow depth-discharge curve, also denoted the rating curve, in the case where the cross section consists of a main channel flanked by floodplains. The problem is solved using piecewise regression, where the changing point is found by optimisation. To avoid entering a local minimum global optimisation has been applied. Moreover, bootstrap inference is introduced to estimate confidence limits for the changing point and other model parameters. The developed method is an elegant, efficient and practically applicable method that can ensure more precise discharge data.

The prize for 2008 was awarded to Johanna Korhonen for the contribution

   Long-term changes in lake ice cover in Finland
   Nordic Hydrology, Vol. 37, No. 4-5, 347-363, 2006

The paper reports a comprehensive analysis of ice conditions in Finland. A huge effort has been done to collect and validate a data set that includes data back from the 19th century. About 90 lakes have been investigated for freeze-up and break-up dates, and about 30 lakes for ice thickness. Interesting results are presented, among those the fact that a significant trends towards later freeze-up and earlier break-up are found, but only if data from the 19th century are included. Other important results relate to ice thickness that has increased during the last 40 years and most probably due to increased snowfall. The paper is well organised, clearly written with appropriate use of tables and figures.

The prize for 2006 was awarded to Steen Christensen for the contribution

   A synthetic groundwater study of the accuracy of GLUE uncertainty intervals
   Nordic Hydrology, Vol. 35, No. 1, 45-59, 2004

The paper provides an important guidance to users of the GLUE technology by clearly pointing out several pitfalls that can lead to wrong conclusions. The impact of small scale variability and choice of sampling scheme and likelihood function is analysed in detail, and it is demonstrated that GLUE in some cases may suggest rejection of a model which in fact should not be rejected. Also, prediction intervals may become rather misleading without proper accounting for measurement errors. The paper is important in raising a warning against uncritical use of GLUE.

The prize for 2004 was awarded to Jan Seibert for the contribution

   Reliability of model predictions outside calibration conditions
   Nordic Hydrology, Vol. 34, No. 5, 477-492, 2003

The paper addresses an important topic of uncertainties in model predictions when used outside calibration conditions and applied for prediction of extreme events. The author shows that improved calibration procedures do not necessarily automatically yield better predictions, which might lead to errors in estimation of design floods. A differential split-sample test used in the study might be a more powerful test of model capabilities, as it allows better tests of the most uncertain predictions. The paper is well written and is valuable for practical applications.

The prize for 2002 was awarded to Urmas Raudsepp for the contribution

   Interannual and seasonal temperature and salinity variations in the Gulf
   of Riga and corresponding saline water inflow from the Baltic Proper

   Nordic Hydrology, Vol. 32, No. 2, 135-160, 2001

This is an excellent paper being multidisciplinary in combining oceanography with hydrology and climatology. In a comprehensive modelling effort the author has succeeded in explaining the observed decreasing trend in salinity superimposed by large interseasonal variability.

The prize for 2000 was awarded to Gísli Már Gíslason, Jón S. Ólafsson and Hákon Adelsteinsson for the contribution

   Animal communities in Icelandic rivers in relation to catchment
   characteristics and water chemistry

    Nordic Hydrology, Vol. 29, No. 2, 129-148, 1998

The paper explains how the chemical composition and nutrient availability are influenced by geology, topography and vegetation cover. This is governing the density and diversity of invertebrates, and, moving up in the food chain, the salmon as well. The biota of Icelandic rivers is found to be strongly influenced by changing land use, where overgrazing and soil erosion have impacted the water balance and the water quality.

The prize for 1998 was awarded to Jan Høybye for the contribution

   Uncertainty analysis in water quality modelling – case study Hjarbæk Fjord
   Nordic Hydrology, Vol. 17, No. 3, 203-214, 1996

The subject of the paper is quantification of prediction uncertainty in deterministic hydrological models. It is successfully shown that first order analysis can be effectively used for calculation of error propagation in certain model types. Reduction of input uncertainty is found to be crucial for the use of more advanced uncertainty estimation tools.

The prize for 1996 was awarded to D. Sheng, K. Axelsson and S. Knutsson for the contributions

   Frost heave due to ice lens formation in freezing soils; 1. Theory and
   verification; 2. Field application

   Nordic Hydrology, Vol. 26, no. 2, 125-168, 1995

The authors have developed a theoretical mathematical model for ice lens formation that has been verified by comparison to field measurements. Its applicability is successfully demonstrated in the solution of practical problems.

The prize for 1994 was awarded to Jan-Gunnar Winther for the contributions

   Landsat thematic mapper (TM) derived reflectance from a mountainous
   watershed during the snow melt season

   Nordic Hydrology, Vol. 23, No. 5, 273-290, 1992
   Short- and Long-term variability of snow albedo
   Nordic Hydrology, Vol. 24, No. 2-3, 199-212, 1993

The author has combined field measurements with satellite information and obtained an improved description of short wave reflection at the snow surface. This creates potential for more precise snowmelt calculations.

The prize for 1992 was awarded to Karsten Høgh Jensen and Jens Christian Refsgaard for the contributions

   Spatial variability of physical parameters and processes in two field soils;
   Part I: Water flow and solute transport at local scale; Part II: Water flow at
   field scale; Part III: Solute transport at field scale

   Nordic Hydrology, Vol. 22, No. 5, 265-340, 1991

The papers describe a series of targeted and well conducted field experiments for which the authors have adjusted and verified a stochastic theory for flow and transport in the unsaturated zone. The demonstrated large spatial variability of soil parameters emphasises the necessity for including more than just a few samples points as basis for flow and transport calculations.

The prize for 1990 was awarded to Lotta Andersson for the contribution

   Hydrological analysis of basin behaviour from soil moisture data
   Nordic Hydrology, Vol. 19, No. 1, 1-18, 1988

Data from the Velen catchment collected during the International Hydrological Decade have been used for water balance modelling studies with focus on interception, evapotranspiration and percolation including macropore effects. The paper successfully explains how much and under which conditions differences in topography, vegetation and soils contribute to the variability in hydrological response within the catchment.