Tiina Nygård

Tiina Nygård
Finnish Meteorological Institute · Meteorology Unit

PhD; Docent

About

36
Publications
4,031
Reads
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735
Citations
Additional affiliations
September 2011 - December 2012
University of Helsinki
Position
  • PostDoc Position
September 2011 - present
Finnish Meteorological Institute
Position
  • Researcher
May 2007 - July 2011
The University Centre in Svalbard
Position
  • Research Fellow/PhD Candidate

Publications

Publications (36)
Article
Full-text available
Thermodynamic profiles are affected by both the large-scale dynamics and the local processes, such as radiation, cloud formation and turbulence. Based on ERA5 reanalysis, radiosoundings and cloud cover observations from winters 2009–2018, this study demonstrates manifold impacts of large-scale circulation on temperature and specific humidity profil...
Article
Full-text available
The transport and distribution of short-lived climate forcers in the Arctic are influenced by the prevailing atmospheric circulation patterns. Understanding the coupling between pollutant distribution and dominant atmospheric circulation types is therefore important, not least to understand the processes governing the local processing of pollutants...
Preprint
Full-text available
Thermodynamic profiles are affected by both the large scale dynamics and the local processes, such as radiation, cloud formation and turbulence. Based on ERA5 reanalysis, radiosoundings and cloud cover observations from winters 2009–2018, this study demonstrates manifold impacts of large scale circulation on temperature and specific humidity profil...
Article
Atmospheric moisture is a key component in the water cycle and radiative transfer. In this study, a comprehensive picture of air moisture climatology and related physical processes is presented for the first time for the circumpolar area south of 50°S. The results are based on the most modern global reanalysis, ERA-5, which manages reasonably well...
Article
Full-text available
It is widely recognized that numerical weather prediction (NWP) results for the Antarctic are relatively poor compared to the mid‐latitudes. In this study, we evaluate output from three operational NWP systems: the ECMWF, Global Forecast System (GFS) and Antarctic Mesoscale Prediction System (AMPS), for the Austral winter (June‐August) of 2013 for...
Article
Along with the amplified warming and dramatic sea ice decline, the Arctic has experienced regionally and seasonally variable moistening of the atmosphere. Based on reanalysis data, this study demonstrates that the regional moistening patterns during the last four decades, 1979– 2018, were predominantly shaped by the strong trends in horizontal mois...
Article
This study gives a comprehensive picture of how atmospheric large-scale circulation is related to moisture transport and to distributions of moisture, clouds, and surface downward longwave radiation in the Arctic in winter. Anomaly distributions of the abovementioned variables are compared in 30 characteristic wintertime atmospheric circulation reg...
Article
Full-text available
Arctic trends of integrated water vapor were analyzed based on four reanalyses and radiosonde data over 1979–2016. Averaged over the region north of 70°N, the Arctic experiences a robust moistening trend that is smallest in March (0.07 ± 0.06 mm decade ⁻¹ ) and largest in August (0.33 ± 0.18 mm decade ⁻¹ ), according to the reanalyses’ median and o...
Article
Full-text available
Plain Language Summary The radiosounding network is a crucial part of the atmospheric observing system, because radiosoundings provide accurate direct information on vertical profiles of temperature, humidity and winds. However, the radiosounding network is sparse in the Arctic; 76 sounding stations are located on continents and islands north of 60...
Article
Horizontal moisture transport has a manifold role in the Arctic climate system as it distributes atmospheric water vapour and thereby shapes the radiative and hydrological conditions. Moisture transport between the Arctic and the mid‐latitudes was examined based on ERA‐Interim reanalysis. The meridional net transport is only a small part of the wat...
Article
The occurrence and characteristics of Arctic specific humidity inversions (SHIs) were examined on the basis of two reanalyses (ERA-Interim and JRA-55) and radiosonde sounding data from 2003 to 2014. Based on physical properties, the SHIs were divided into two main categories: SHIs below and above the 800-hPa level. Above the 800-hPa level, SHIs occ...
Article
The occurrence, properties and temporal variations of temperature inversions over Dronning Maud Land, Antarctica, were examined on the basis of tethersonde and 10-m tower measurements during the austral summer 2010–2011. Temperature inversions occurred in 96% of the observed tethersonde profiles, and a surface-based inversion in 58% of the profiles...
Article
Full-text available
Dynamics of atmosphere–ice–ocean interactions in the high latitudes. What: Scientists from 13 countries involved with modeling and observing the coupled high-latitude weather and climate system discussed our current understanding and challenges in polar prediction, extreme events, and coupled processes on scales ranging from cloud and turbulent pro...
Article
Eight atmospheric reanalyses were compared against observed vertical profiles of temperature, specific humidity and wind speed collected by two research aircraft in February–March 2010 in the Antarctic Peninsula region. These data offered a rare possibility to validate reanalyses against independent in-situ data which have not been assimilated into...
Article
Full-text available
An analysis of Special Sensor Microwave/Imager (SSM/I) satellite data reveals that the Whaler’s Bay polynya north of Svalbard was considerably larger in the three winters from 2012 to 2014 compared to the previous 20 years. This increased polynya size leads to strong atmospheric convection during cold air outbreaks in a region north of Svalbard tha...
Article
Full-text available
The Arctic climate system includes numerous highly interactive small-scale physical processes in the atmosphere, sea ice, and ocean. During and since the International Polar Year 2007–2009, significant advances have been made in understanding these processes. Here, these recent advances are reviewed, synthesized, and discussed. In atmospheric physi...
Article
Full-text available
An analysis of SSM/I satellite data reveals that the Whaler's Bay Polynya north of Svalbard was considerably larger in the last three winters from 2012 to 2014 compared to the previous 20 years. This increased polynya size leads to strong atmospheric convection during cold air outbreaks in a region north of Svalbard that typically was ice covered i...
Article
Full-text available
Humidity inversions have a high potential importance in the Arctic climate system, especially for cloud formation and maintenance, in wide spatial and temporal scales. Here we investigate the climatology and characteristics of humidity inversions in the Arctic, including their spatial and temporal variability, sensitivity to the methodology applied...
Article
The summer atmospheric boundary layer over a fjord in the High Arctic has been investigated during three consecutive years (2008–2010). Measurements of turbulent surface layer fluxes of momentum and sensible heat using a sonic anemometer and slow-response instruments were taken from a tower on the coast of Isfjorden, Svalbard, and analysed for seas...
Article
Full-text available
Humidity inversions have a high potential importance in the Arctic climate system, especially for cloud formation and maintenance, in wide spatial and temporal scales. Here we investigate the climatology and characteristics of humidity inversions in the Arctic, including their spatial and temporal variability, sensitivity to the methodology applied...
Article
Humidity inversions are nearly permanently present in the coastal Antarctic atmosphere. This is shown based on an investigation of statistical characteristics of humidity inversions at 11 Antarctic coastal stations using radiosonde data from the Integrated Global Radiosonde Archive (IGRA) from 2000 to 2009. The humidity inversion occurrence was hig...
Article
The vertical structure of the atmospheric boundary layer (ABL), simulated with the mesoscale model Weather Research and Forecasting (WRF) as well as with its polar optimized version Polar WRF, was compared to tethered balloon soundings and mast observations taken in March and April 2009 from two Arctic fjords in Svalbard. From twelve short (48 h) s...
Article
Numerical weather prediction and climate models continue to have large errors for stable boundary layers (SBL). To understand and to improve on this, so far three atmospheric boundary layer model inter-comparison studies have been organised within the Global Energy and Water Cycle Experiment (GEWEX) of the World Climate Research Programme (WCRP). T...
Article
Full-text available
Air temperature and specific humidity inversions and low-level jets were studied over two Svalbard fjords, Isfjorden and Kongsfjorden, applying three tethersonde systems. Tethersonde operation practices notably affected observations on inversion and jet properties. The inversion strength and depth were strongly affected by weather conditions at the...
Article
Momentum and sensible heat exchange are studied in an Arctic fjord system in Spitsbergen, Svalbard (Norway), based on tower measurements taken in January–June 2008. Due to ice-free conditions, the surface layer was unstable for most of the time, occasionally very unstable. The shape of the fjord and the surrounding topography have a large influence...
Article
The spatial variability of near-surface variables and turbulent surface fluxes was investigated in three Arctic fjords in Svalbard applying the Weather Research and Forecasting (WRF) mesoscale model. Ten real cases from winter and spring 2008, representing the most common large-scale flow directions, were simulated at 9, 3 and 1 km resolutions for...
Article
The atmospheric boundary layer (ABL) over Arctic fjords is poorly understood and many processes occur on spatial scales that cannot be resolved by climate and weather prediction models. The meteorological conditions over a fjord are largely affected by surrounding complex topography, sea ice cover and oceanographic phenomena. This study addresses t...
Article
Full-text available
The recurrence of heavy precipitation, dry spells and deep snow cover were estimated based on observations at about ten stations in Finland during about five decades. The 10-year return levels were assessed by means of the so-called "peak over threshold" (POT) method. The return levels of the annual maximum snow depth ranged from about 65 cm in sou...
Article
Full-text available
Rainfall data, collected with a continuously-recording rain gauge in Helsinki, southern Finland, during the summers of the period 1951-2000 were used to study the climatology of the transient characteristics of summer precipitation. Despite some missing data and erroneous values, the quality of the data proved to be good. According to the observati...
Article
Full-text available
The atmospheric boundary layer (ABL) in polar areas is poorly understood, especially where complex topography has an influence on its structure. Air-ice-sea interactions have been studied during several field campaigns (e.g. SHEBA, Uttal et al., 2002) that usually took place further away from coast and from significant influence of topography. In a...

Projects

Projects (4)
Project
PolarRES will study the interactions between the atmosphere, oceans, and sea ice in the Arctic and Antarctic to provide new insights into the key physical and chemical processes of these interactions on a local and regional level. We will assess how the processes respond to and influence projected changes in the global circulation and what this means for the society and the environment.
Project
The overall goal of AFEC is to better understand direct and indirect effects of the Arctic on European weather and climate, and how these effects have changed due to the Arctic Amplification of climate warming.
Project
The overall aim of ASPIRE is to better understand physical processes in the Antarctic atmosphere and snow, and to apply this understanding in improving weather and climate predictions.