Eirik Førland - Academia.edu (original) (raw)

Papers by Eirik Førland

Research paper thumbnail of Distribution of snow cover over Northern Eurasia

Hydrology Research

Based on observation data the spatial variability and long-term trends of snow depth, snow water ... more Based on observation data the spatial variability and long-term trends of snow depth, snow water equivalent and number of days with snow coverage ≥50% for Northern Eurasia are estimated. The significance of continental snow cover variability over Northern Eurasia is illustrated by comparison with snow cover variability of the northern part of North America (Canada). The fundamental scientific problem of our investigations is revealing spatial and temporal changes of snow cover under the present climate conditions. The snow cover depends on a climate on the one hand and appreciably defines a hydrological regime on the other hand and, thus, the snow cover is a good indicator of changes in the condition of an environment. In this case the condition of the snow cover of the Northern hemisphere on an example of Northern Eurasia within the boundaries of the NIS and the northern part of North America within the boundaries of Canada is investigated. The novelty of the work, in particular, c...

Research paper thumbnail of Climate impacts on the ice regime of an Atlantic river

Hydrology Research

Although the sensitivity of river ice processes to climatic inputs is well known, there is very l... more Although the sensitivity of river ice processes to climatic inputs is well known, there is very little information on how a changing climate can affect the severity and frequency of ice jam events and their numerous ecological and socio-economic impacts. The present study adds to this information by examining the ice regime of the Southwest Miramichi River, New Brunswick, and identifying recent trends that may be linked to concomitant climatic variations. The timing of freeze-up and breakup, as well as the thickness of the winter ice cover, do not exhibit significant temporal trends. However, spring ice jamming is becoming more severe, and there is increasing potential for devastating mid-winter breakup events. These findings are consistent with increasing rainfall and snowfall amounts, as well as increasing river flows, during the winter and early spring. Unlike in most parts of Canada, slight cooling during the winter months was detected, consistent with cooling trends found elsew...

Research paper thumbnail of Estimating Regional Precipitation Trends Comparison of two Methods

Hydrology Research

Two different methods were applied to estimate long-term precipitation trends representative for ... more Two different methods were applied to estimate long-term precipitation trends representative for regions in Norway. A new method, comparative trend analysis (CTA), was applied on 142 homogeneous precipitation series of 70-100 years. In this way 12 precipitation trend regions were identified. Principal component analysis (PCA) was applied on a subset of 30 series during the period 1896-1994 The results from both analyses were used to estimate precipitation trend series at several locations. The estimates based upon the PCA were of same quality as the estimates based upon the CTA. However, by CTA it is possible to visualize the trend in a distinct region by using just one trend curve, while trend curves based on PCA are composed of contributions from 5 principal components. The resulting trend curves document that the annual precipitation level has increased by 8-14% throughout this century in most Norwegian regions. The increase occurred not simultaneously all over the country. The r...

Research paper thumbnail of Utviklingen av naturulykker som f�lge av klimaendringer

Research paper thumbnail of Long-term climate trends of the Yamalo-Nenets AO, Russia

... T ARKO-SALE - 1953.-.06 23330 SALEKHARD 1973 - 1956.-.02 23032 MARE-SALE - 1951 29.08 23445 N... more ... T ARKO-SALE - 1953.-.06 23330 SALEKHARD 1973 - 1956.-.02 23032 MARE-SALE - 1951 29.08 23445 NAD YM - - T able 2: Relocation of the meteorological stations at the Y amal p eninsula (Svyashchennikov, 2010). WMO num b er Station name Jan Feb Mar Apr May Jun ...

Research paper thumbnail of Snow water equivalent mapping in Norway

In high latitude area snow covers the ground large parts of the year. Information about the water... more In high latitude area snow covers the ground large parts of the year. Information about the water volume as snow is of major importance in many respects. Flood forecasters at NVE need it in order to assess possible flood risks. Hydropower producers need it to plan the most efficient production of the water in their reservoirs, traders to estimate the

Research paper thumbnail of Recent changes in the frequency of freezing precipitation in North America and Northern Eurasia

Environmental Research Letters, 2016

Research paper thumbnail of Increased Precipitation in the Norwegian Arctic: True or False?

Climatic Change, Aug 31, 2000

Research paper thumbnail of Estimation of extreme precipitation; Return period values and PMP for Norway

Egu General Assembly Conference Abstracts, May 1, 2010

Research paper thumbnail of Long-term climate trends of Finnmarksvidda, Northern-Norway

Research paper thumbnail of Changes in “normal” precipitation in the North Atlantic region

Research paper thumbnail of Energy demand and potential for hydropower production in Norway Historic and future perspective

Research paper thumbnail of Snow cover and snow water equivalent in Norway - Current conditions (1961–1990) and scenarios for the future (2071–2100)

Research paper thumbnail of Local Climate Scenarios for Norway Based on MPI’s ECHAM/OPYC3, a New DNMI Data Analysis, and the Common EOF Method

Detecting and Modelling Regional Climate Change, 2001

Research paper thumbnail of Long-term trends in temperature, precipitation and snow conditions in Northern Russia

Research paper thumbnail of Trends in extreme precipitation and return values in Norway 1900-2004

Research paper thumbnail of Evaluation and Analysis of the ECHAM4/OPYC3 GSDIO-Integration Temperature- and SLP-Fields over Norway and Svalbard

Detecting and Modelling Regional Climate Change, 2001

Research paper thumbnail of Changes in Temperature and Precipitation in the Norwegian Arctic during the 20th Century

Detecting and Modelling Regional Climate Change, 2001

Research paper thumbnail of Estimating extreme areal precipitation in Norway from a gridded dataset

Hydrological Sciences Journal, 2014

Research paper thumbnail of Snow map system for Norway

ABSTRACT During the winter 2004 new methods are developed by NVE and met.no to produce snow maps ... more ABSTRACT During the winter 2004 new methods are developed by NVE and met.no to produce snow maps accounting for accumulation, melt, refreezing and winter rain. The maps substitute traditional snow accumulation maps, and are daily products updated on a weekly basis. Spatial estimation of temperature and precipitation is applied to observations from the Norwegian meteorological network. A snow model operating on a 1x1 km 2 and one-day resolution is used. The development of a web-and GIS-based system for producing the maps is presented. GIS technology is used for spatial estimation of weather elements, snow simulation during the winter, and presenting results as maps in order to serve Government and local authorities in early-warning of floods and hydro-electricity production and distribution shortages. A suite of 20 maps are produced daily and presented to users in web-and GIS-based interfaces. Maps of snow water equivalent (percent of normal, millimetres and rank), snow melt, runoff, snow state, fresh snow, snow age, snow depth and snow energy equivalent show daily and weekly totals or change. Web-based interfaces provide easy access and navigation in a 300,000-map archive from 1962. Snow maps combine with hydrology and energy-related data in ArcGIS and ArcIMS.

Research paper thumbnail of Distribution of snow cover over Northern Eurasia

Hydrology Research

Based on observation data the spatial variability and long-term trends of snow depth, snow water ... more Based on observation data the spatial variability and long-term trends of snow depth, snow water equivalent and number of days with snow coverage ≥50% for Northern Eurasia are estimated. The significance of continental snow cover variability over Northern Eurasia is illustrated by comparison with snow cover variability of the northern part of North America (Canada). The fundamental scientific problem of our investigations is revealing spatial and temporal changes of snow cover under the present climate conditions. The snow cover depends on a climate on the one hand and appreciably defines a hydrological regime on the other hand and, thus, the snow cover is a good indicator of changes in the condition of an environment. In this case the condition of the snow cover of the Northern hemisphere on an example of Northern Eurasia within the boundaries of the NIS and the northern part of North America within the boundaries of Canada is investigated. The novelty of the work, in particular, c...

Research paper thumbnail of Climate impacts on the ice regime of an Atlantic river

Hydrology Research

Although the sensitivity of river ice processes to climatic inputs is well known, there is very l... more Although the sensitivity of river ice processes to climatic inputs is well known, there is very little information on how a changing climate can affect the severity and frequency of ice jam events and their numerous ecological and socio-economic impacts. The present study adds to this information by examining the ice regime of the Southwest Miramichi River, New Brunswick, and identifying recent trends that may be linked to concomitant climatic variations. The timing of freeze-up and breakup, as well as the thickness of the winter ice cover, do not exhibit significant temporal trends. However, spring ice jamming is becoming more severe, and there is increasing potential for devastating mid-winter breakup events. These findings are consistent with increasing rainfall and snowfall amounts, as well as increasing river flows, during the winter and early spring. Unlike in most parts of Canada, slight cooling during the winter months was detected, consistent with cooling trends found elsew...

Research paper thumbnail of Estimating Regional Precipitation Trends Comparison of two Methods

Hydrology Research

Two different methods were applied to estimate long-term precipitation trends representative for ... more Two different methods were applied to estimate long-term precipitation trends representative for regions in Norway. A new method, comparative trend analysis (CTA), was applied on 142 homogeneous precipitation series of 70-100 years. In this way 12 precipitation trend regions were identified. Principal component analysis (PCA) was applied on a subset of 30 series during the period 1896-1994 The results from both analyses were used to estimate precipitation trend series at several locations. The estimates based upon the PCA were of same quality as the estimates based upon the CTA. However, by CTA it is possible to visualize the trend in a distinct region by using just one trend curve, while trend curves based on PCA are composed of contributions from 5 principal components. The resulting trend curves document that the annual precipitation level has increased by 8-14% throughout this century in most Norwegian regions. The increase occurred not simultaneously all over the country. The r...

Research paper thumbnail of Utviklingen av naturulykker som f�lge av klimaendringer

Research paper thumbnail of Long-term climate trends of the Yamalo-Nenets AO, Russia

... T ARKO-SALE - 1953.-.06 23330 SALEKHARD 1973 - 1956.-.02 23032 MARE-SALE - 1951 29.08 23445 N... more ... T ARKO-SALE - 1953.-.06 23330 SALEKHARD 1973 - 1956.-.02 23032 MARE-SALE - 1951 29.08 23445 NAD YM - - T able 2: Relocation of the meteorological stations at the Y amal p eninsula (Svyashchennikov, 2010). WMO num b er Station name Jan Feb Mar Apr May Jun ...

Research paper thumbnail of Snow water equivalent mapping in Norway

In high latitude area snow covers the ground large parts of the year. Information about the water... more In high latitude area snow covers the ground large parts of the year. Information about the water volume as snow is of major importance in many respects. Flood forecasters at NVE need it in order to assess possible flood risks. Hydropower producers need it to plan the most efficient production of the water in their reservoirs, traders to estimate the

Research paper thumbnail of Recent changes in the frequency of freezing precipitation in North America and Northern Eurasia

Environmental Research Letters, 2016

Research paper thumbnail of Increased Precipitation in the Norwegian Arctic: True or False?

Climatic Change, Aug 31, 2000

Research paper thumbnail of Estimation of extreme precipitation; Return period values and PMP for Norway

Egu General Assembly Conference Abstracts, May 1, 2010

Research paper thumbnail of Long-term climate trends of Finnmarksvidda, Northern-Norway

Research paper thumbnail of Changes in “normal” precipitation in the North Atlantic region

Research paper thumbnail of Energy demand and potential for hydropower production in Norway Historic and future perspective

Research paper thumbnail of Snow cover and snow water equivalent in Norway - Current conditions (1961–1990) and scenarios for the future (2071–2100)

Research paper thumbnail of Local Climate Scenarios for Norway Based on MPI’s ECHAM/OPYC3, a New DNMI Data Analysis, and the Common EOF Method

Detecting and Modelling Regional Climate Change, 2001

Research paper thumbnail of Long-term trends in temperature, precipitation and snow conditions in Northern Russia

Research paper thumbnail of Trends in extreme precipitation and return values in Norway 1900-2004

Research paper thumbnail of Evaluation and Analysis of the ECHAM4/OPYC3 GSDIO-Integration Temperature- and SLP-Fields over Norway and Svalbard

Detecting and Modelling Regional Climate Change, 2001

Research paper thumbnail of Changes in Temperature and Precipitation in the Norwegian Arctic during the 20th Century

Detecting and Modelling Regional Climate Change, 2001

Research paper thumbnail of Estimating extreme areal precipitation in Norway from a gridded dataset

Hydrological Sciences Journal, 2014

Research paper thumbnail of Snow map system for Norway

ABSTRACT During the winter 2004 new methods are developed by NVE and met.no to produce snow maps ... more ABSTRACT During the winter 2004 new methods are developed by NVE and met.no to produce snow maps accounting for accumulation, melt, refreezing and winter rain. The maps substitute traditional snow accumulation maps, and are daily products updated on a weekly basis. Spatial estimation of temperature and precipitation is applied to observations from the Norwegian meteorological network. A snow model operating on a 1x1 km 2 and one-day resolution is used. The development of a web-and GIS-based system for producing the maps is presented. GIS technology is used for spatial estimation of weather elements, snow simulation during the winter, and presenting results as maps in order to serve Government and local authorities in early-warning of floods and hydro-electricity production and distribution shortages. A suite of 20 maps are produced daily and presented to users in web-and GIS-based interfaces. Maps of snow water equivalent (percent of normal, millimetres and rank), snow melt, runoff, snow state, fresh snow, snow age, snow depth and snow energy equivalent show daily and weekly totals or change. Web-based interfaces provide easy access and navigation in a 300,000-map archive from 1962. Snow maps combine with hydrology and energy-related data in ArcGIS and ArcIMS.