Norwegian Hydrological Reference Dataset for Climate Change Studies Anne K. Fleig (Ed.) 2 2013 RAPPORT Norwegian Hydrological Reference Dataset for Climate Change Studies Norwegian Water Resources and Energy Directorate 2013 Report no. 2 – 2013 Norwegian Hydrological Reference Dataset for Climate Change Studies Published by: Norwegian Water Resources and Energy Directorate Editor: Anne K. Fleig Authors: Anne K. Fleig, Liss M. Andreassen, Emma Barfod, Jonatan Haga, Lars Egil Haugen, Hege Hisdal, Kjetil Melvold, Tuomo Saloranta Print: Norwegian Water Resources and Energy Directorate Number printed: 50 Femundsenden, spring 2000, Photo: Vidar Raubakken and Cover photo: Gunnar Haugen, NVE. ISSN: 1501-2832 ISBN: 978-82-410-0869-6 Abstract: Based on the Norwegian hydrological measurement network, NVE has selected a Hydrological Reference Dataset for studies of hydrological change. The dataset meets international standards with high data quality. It is suitable for monitoring and studying the effects of climate change on the hydrosphere and cryosphere in Norway. The dataset includes streamflow, groundwater, snow, glacier mass balance and length change, lake ice and water temperature in rivers and lakes. Key words: Reference data, hydrology, climate change Norwegian Water Resources and Energy Directorate Middelthunsgate 29 P.O. Box 5091 Majorstua N 0301 OSLO NORWAY Telephone: +47 22 95 95 95 Fax: +47 22 95 90 00 E-mail: [email protected] Internet: www.nve.no January 2013 Contents Preface ................................................................................................. 5 Summary ............................................................................................. 6 1 Introduction ................................................................................... 7 2 Selection criteria for a Hydrological Reference Dataset ........... 8 3 Data and criteria for the Norwegian HRD ................................... 9 3.1 Streamflow .......................................................................................9 3.1.1 Available data ..........................................................................9 3.1.2 Selection of streamflow stations ..............................................9 3.2 Soil moisture ..................................................................................18 3.2.1 Available data ........................................................................18 3.3 Groundwater ..................................................................................19 3.3.1 Available data ........................................................................19 3.3.2 Selection of groundwater stations ......................................... 19 3.4 Snow ..............................................................................................21 3.4.1 Available data ........................................................................21 3.4.2 Selection of snow stations .....................................................22 3.5 Glaciers ..........................................................................................23 3.5.1 Available data ........................................................................23 3.5.2 Selection of glacier stations ...................................................24 3.6 Lake and river ice ...........................................................................27 3.6.1 Available data ........................................................................27 3.6.2 Selection of lake and river stations ........................................27 3.7 River and lake temperature ............................................................28 3.7.1 Available data ........................................................................28 3.7.2 Selection of river and lake temperature stations ................... 29 4 Final reference datasets ............................................................. 30 4.1 Streamflow .....................................................................................30 4.1.1 Reference series ...................................................................30 4.1.2 Map .......................................................................................32 4.1.3 Catchment characteristics .....................................................35 4.2 Groundwater ..................................................................................35 4.2.1 Reference series ...................................................................35 4.2.2 Map .......................................................................................37 4.3 Snow ..............................................................................................38 4.3.1 Reference series ...................................................................38 4.3.2 Map .......................................................................................40 4.4 Glaciers ..........................................................................................41 4.4.1 Reference series ...................................................................41 4.4.2 Map .......................................................................................42 4.4.3 Station characteristics ...........................................................43 4.5 Lake and river ice ...........................................................................44 4.5.1 Reference series ...................................................................44 4.5.2 Map .......................................................................................45 4.5.3 Station characteristics .......................................................... 45 4.6 River and lake temperature ........................................................... 46 4.6.1 Reference series .................................................................. 46 4.6.2 Map ....................................................................................... 53 4.6.3 Station characteristics .......................................................... 53 5 Further work ................................................................................ 54 5.1 Improving the streamflow RD ........................................................ 54 5.2 Improving the soil moisture RD ..................................................... 55 5.3 Improving the groundwater RD ...................................................... 55 5.4 Improving the snow RD ................................................................. 55 5.5 Improving the glacier RD ............................................................... 56 5.6 Improving the lake and river ice RD .............................................. 56 5.7 Improving the river and lake temperature RD ................................ 56 5.8 Maintaining the Hydrological Reference Dataset .......................... 57 Acknowledgements ........................................................................... 57 References ......................................................................................... 58 Appendix 1: Streamflow reference dataset ..................................... 60 Summary This report presents an action undertaken according to NVE’s Strategy for Climate Change Adaption. There it is stated that a Norwegian Hydrological Reference Dataset suitable to study climate change effects on hydrology needs to be established as a basis to fulfil NVE’s responsibility to monitor the effects of climate change and to improve knowledge about climate change related processes and impacts. Such a Hydrological Reference Dataset (HRD) needs to consist of long, high quality data series that are not affected by human activity causing non-climate related variability or change. The here presented HRD for Norway is selected from NVE’s existing station network for the hydrosphere and cryosphere, including streamflow, soil moisture, groundwater, snow, glacier mass balance and length, lake and river ice and water temperature in rivers and lakes. The selection criteria follow international standards and cover the degree of basin development and water usage, record length, data accuracy and available metadata. Depending on the fulfilment of these criteria some stations are assigned limited usability for certain kind of studies. The total resulting HRD consists of 189 streamflow series, 28 groundwater series, 68 snow water equivalent series, 9 series of glacier mass balance and 11 of glacier length, 22 lake ice and 2 river ice duration series as well as 9 water temperature series for rivers and 37 for lakes. Currently none of the existing soil moisture series are long enough to meet the requirements. For most of the variables, however, some parts of the country are underrepresented or not covered. 6 1 Introduction In recent decades, changes in climate, and in particular increased temperatures, have been observed (Solomon et al., 2007). In Norway, temperatures have increased and there have been regional changes in precipitation and annual runoff, as well as increased winter and spring runoff and earlier snowmelt (Wilson et al., 2010). A continued increase in temperature and precipitation (except for the summer season) is predicted (Hanssen- Bauer et al., 2009). More frequent episodes of extreme rainfall are also anticipated. Changes in climate are expected to lead to changes in hydrology, with increasing annual runoff, and greater runoff in the autumn and winter and less during summer (Beldring et al., 2008). Increased floods are expected in all rivers except for large