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ABOUT

PERSONAL DETAILS
Nygårdsgaten 112, Bergen
erik.kolstad at uni.no
+47 555 82432
+47 411 22457
Welcome to my personal and academic profile
This page is under construction

BIO

ABOUT ME

Hi, and thanks for visiting this page. You're probably here because of my work in climate research; please click on the WORK tab for more info about that. In addition to loving my work in research, I'm also passionate about hiking, skiing, travelling and photography.

CURRENT

I’m a researcher at Uni Research and the Bjerknes Centre for Climate Research at the University of Bergen, Norway.

SUNCURVES

I’m a co-founder of Suncurves, where we compute actual times for sunrise and sunset, accounting for shading from terrain.

PHOTOGRAPHY

If you're interested, please check out my portfolio at 500px.


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RESUME

  • EDUCATION
  • 2003
    2007
    Bergen, Norway

    Ph.D. in meteorology

    University of Bergen

    Thesis: Extreme winds in the Nordic Seas: polar lows and Arctic fronts in a changing climate
  • 1993
    1997
    Bergen, Norway

    M.Sc. in applied mathematics

    University of Bergen

    Thesis: Stability of a tokamak in the presence of a resistive wall
  • 1992
    1993
    Toulouse, France

    Undergraduate studies

    INSA Toulouse

    First year of technical college
  • ACADEMIC AND PROFESSIONAL POSITIONS
  • 2014
    NOW
    Bergen, Norway

    Senior Researcher

    Uni Research Climate and Bjerknes Centre for Climate Research

    My current position
  • 2011
    2014
    Bergen, Norway

    Senior Researcher and Developer

    StormGeo

    I spent three years at StormGeo, a commercial weather company, where I oversaw all operational forecasts and hindcasts using WRF
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PUBLICATIONS

PUBLICATIONS LIST
AUG 2016

Causal Chains for Attributing Temperature Persistence to Physical Mechanisms: Applications to Northern Europe

Quarterly Journal of the Royal Meteorological Society

The purpose of this paper is to develop a framework to identify the mechanisms that drive atmospheric persistence, using causal chains and lagged linear regressions

Journal Paper Submitted EW Kolstad, EA Barnes, and SP Sobolowski

Causal Chains for Attributing Temperature Persistence to Physical Mechanisms: Applications to Northern Europe

Erik W. Kolstad, Elizabeth A. Barnes, and Stefan P. Sobolowski

Submitted to QJRMS

Abstract

Weather persistence from month to month is an important source of predictability on the intraseasonal time scale. Persistence in the lower troposphere is mainly due to dynamical feedbacks between the chaotic and rapidly evolving atmospheric flow and more inert physical variables at or below the surface. Many recent improvements of dynamical seasonal forecasting models have been due to better initialisations and representations of the lower boundary. However, not all of the physical mechanisms that mediate persistence are currently understood, hindering the full use of actual sources of predictability in the earth system. The purpose of this paper is to develop a framework to identify the mechanisms that drive atmospheric persistence, using causal chains and lagged linear regressions. While the focus is on Northern Europe, where the annual cycle of the persistence of near-surface temperature is shown to be caused by fluctuating influences of soil moisture, soil temperature, snow cover, and sea surface temperature. The framework outlined here, however, can be applied to the persistence of any variable in any region. A more complete understanding and mapping of the physical mechanisms for atmospheric persistence will not only improve the dynamical models themselves, but also support hybrid forecasting systems where empirical data are combined with model data to yield more skilful seasonal weather forecasts.

JUL 2016

Re-examining the roles of surface heat flux and latent heat release in a “hurricane-like” polar low over the Barents Sea

Journal of Geophysical Research Atmospheres

Here the roles of surface heat fluxes and latent heat release in the development of a Barents Sea polar low, which in its cloud structures showed some similarities to hurricanes, are studied with an ensemble of sensitivity experiments, where latent heating and/or surface fluxes of sensible and latent heat were switched off before the polar low peaked in intensity

Journal Paper EW Kolstad, TJ Bracegirdle, and M Zahn

Re-examining the roles of surface heat flux and latent heat release in a “hurricane-like” polar low over the Barents Sea

Erik W. Kolstad, Thomas J. Bracegirdle, and Matthias Zahn

J. Geophys. Res. Atmos., 121, 7853–7867, doi:10.1002/2015JD024633

Abstract

Polar lows are intense mesoscale cyclones that occur at high latitudes in both hemispheres during winter. Their sometimes evidently convective nature, fueled by strong surface fluxes and with cloud-free centers, have led to some polar lows being referred to as “arctic hurricanes.” Idealized studies have shown that intensification by hurricane development mechanisms is theoretically possible in polar winter atmospheres, but the lack of observations and realistic simulations of actual polar lows have made it difficult to ascertain if this occurs in reality. Here the roles of surface heat fluxes and latent heat release in the development of a Barents Sea polar low, which in its cloud structures showed some similarities to hurricanes, are studied with an ensemble of sensitivity experiments, where latent heating and/or surface fluxes of sensible and latent heat were switched off before the polar low peaked in intensity. To ensure that the polar lows in the sensitivity runs did not track too far away from the actual environmental conditions, a technique known as spectral nudging was applied. This was shown to be crucial for enabling comparisons between the different model runs. The results presented here show that (1) no intensification occurred during the mature, postbaroclinic stage of the simulated polar low; (2) surface heat fluxes, i.e., air-sea interaction, were crucial processes both in order to attain the polar low’s peak intensity during the baroclinic stage and to maintain its strength in the mature stage; and (3) latent heat release played a less important role than surface fluxes in both stages.

JUN 2016

Sensitivity of an Apparently Hurricane-like Polar Low to Sea Surface Temperature

Quarterly Journal of the Royal Meteorological Society

The purpose of this paper is to develop a framework to identify the mechanisms that drive atmospheric persistence, using causal chains and lagged linear regressions

Journal Paper Submitted EW Kolstad, and TJ Bracegirdle

Sensitivity of an Apparently Hurricane-like Polar Low to Sea Surface Temperature

Erik W. Kolstad, and Thomas J. Bracegirdle

Submitted to QJRMS

Abstract

N/A

JUL 2015

Intraseasonal Persistence of European Surface Temperatures

Journal of Climate

A simple, linear approach is used to identify previously undocumented persistence in northern European summer and winter temperature anomalies in climate model simulations, corroborated by observations and reanalysis data

Journal Paper EW Kolstad, SP Sobolowski, and AA Scaife

Intraseasonal Persistence of European Surface Temperatures

Erik W. Kolstad, Stefan P. Sobolowski, and Adam A. Scaife

J. Climate, 28, 5365–5374

Abstract

Recent periods of extreme weather in Europe, such as the cold winter of 2009/10, have caused widespread impacts and were remarkable because of their persistence. It is therefore of great interest to improve the ability to forecast such events. Weather forecasts at midlatitudes generally show low skill beyond 5–10 days, but long-range forecast skill may increase during extended tropospheric blocking episodes or perturbations of the stratospheric polar vortex, which can affect midlatitude weather for several weeks at a time. Here a simple, linear approach is used to identify previously undocumented persistence in northern European summer and winter temperature anomalies in climate model simulations, corroborated by observations and reanalysis data. For instance, temperature anomalies of at least one standard deviation above or below climatology in March were found to be about 20%–120% more likely than normal if the preceding February was anomalous by 0.5–1.5 standard deviations (with the same sign). The corresponding range for April (i.e., persistence over two months) is between 20% and 80%. The persistence is observed irrespective of the data source or driving mechanisms, and the temperature itself is a more skillful predictor of the temperatures one month ahead than the stratospheric polar vortex or the NAO and even than both factors together. The results suggest potential to conditionally improve the skill of long-range forecasts and enhance recent advancements in dynamical seasonal prediction.

JAN 2015

Extreme small-scale wind episodes over the Barents Sea: When, where and why?

Climate Dynamics

The most extreme small-scale wind episodes in the Barents Sea in a high-resolution (5 km) 35-year hindcast were analyzed, and it was found that they were associated with unusually strong low-level baroclinicity and surface heat fluxes

Journal Paper EW Kolstad

Extreme small-scale wind episodes over the Barents Sea: When, where and why?

Erik W. Kolstad

Clim Dyn (2015) 45: 2137

Abstract

The Barents Sea is mostly ice-free during winter and therefore prone to severe weather associated with marine cold air outbreaks, such as polar lows. With the increasing marine activity in the region, it is important to study the climatology and variability of episodes with strong winds, as well as to understand their causes. Explosive marine cyclogenesis is usually caused by a combination of several mechanisms: upper-level forcing, stratospheric dry intrusions, latent heat release, surface energy fluxes, low-level baroclinicity. An additional factor that has been linked to extremely strong surface winds, is low static stability in the lower atmosphere, which allows for downward transfer of high-momentum air. Here the most extreme small-scale wind episodes in a high-resolution (5 km) 35-year hindcast were analyzed, and it was found that they were associated with unusually strong low-level baroclinicity and surface heat fluxes. And crucially, the 12 most severe episodes had stronger cold-air advection than 12 slightly less severe cases, suggesting that marine cold air outbreaks are the most important mechanism for extreme winds on small spatial scales over the Barents Sea. Because weather models are often unable to explicitly forecast small-scale developments in data-sparse regions such as the Barents Sea, these results can be used by forecasters as supplements to forecast model data.