Analysis of a 7-year low-level temperature inversion data set measured at the 280 m high Hamburg weather mast

Brümmer, Burghard; Schultze, Markus

doi:10.1127/metz/2015/0669

Cited by 24 publications

(26 citation statements)

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“…Topographical conditions play a significant role regarding the types and properties of the surface or its cover. The significance of radiative processes that determine both the 24-h and annual basic characteristics of surface-based inversions occurring across the European continent is presented in numerous studies (Brümmer and Schultze 2015;Kassomenos et al 2014;Palarz et al 2017;Stryhal et al 2017). Intense and effective radiation emissions under anticyclonic weather conditions, particularly on cloudless nights or night with small cloud cover and little wind, are the underlying cause of the frequent occurrence of inversion layers with great thicknesses and high vertical temperature gradients during the warmer months of the year.…”

Section: Discussionmentioning

confidence: 99%

“…TIs are usually defined by a layer of the atmosphere where the vertical temperature gradient changes from negative to positive (Whiteman 2000;Stryhal et al 2017;Czarnecka et al 2016). Based on formation mechanisms, atmospheric inversions can usually be classified as radiation inversions, advection inversions, turbulence inversions, subsidence inversions, frontal inversions, 0°C inversions, tropopause inversions and mesospheric inversions (Schnelle and Brown 2002;Nodzu et al 2006;Randel et al 2007;Kumar et al 2001;Gramsch et al 2014;Brümmer and Schultze 2015).…”

Section: Introductionmentioning

confidence: 99%

“…It should be noted that most studies on inversions are restricted to surface inversions or initial elevated inversions only (e.g. Knozová 2008;Iyer and Nagar 2011;Brümmer and Schultze 2015;Stryhal et al 2017;Czarnecka et al 2016). The analysis of the long-term measurement series has shown a decrease in the frequency of surface inversions and a simultaneous increase in the frequency of elevated inversions.…”

Section: Introductionmentioning

confidence: 99%

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Temporal structure of thermal inversions in Łeba (Poland)

Czarnecka

Nidzgorska-Lencewicz

Rawicki

2018

Theor Appl Climatol

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This study presents the detailed characteristics of thermal inversions based on a 10-year aerological measurement series (2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) conducted in Łeba (Poland). The analyses included surface-based inversions (SBIs) and elevated inversions (ELIs) in the atmospheric layer up to 3000 m. In the case of SBIs, this layer extended directly from the ground level to an altitude above which the air temperature decreases with altitude, whereas for ELIs, which have a base above ground level, only the lowermost inversion layer was taken into consideration. The results of the monthly and seasonal variations in the selected parameters for air temperature inversions (thickness-ΔZ, strength-ΔT, base-Z B ) were analysed separately at night-time (00 UTC) and daytime (12 UTC). The thermal structure of the boundary layer up to 3000 m was primarily determined by ELIs, which occurred at a frequency of approximately 70% at both times during the 24-h period. The SBIs showed a pronounced temporal structure that occurred every second night throughout the year and from April to September, with a frequency similar to that of the ELI (approximately 60%). The worst vertical air exchange conditions, which resulted from the simultaneous occurrence of SBIs and ELIs, were found in 30% of nights from April to October. Elevated inversions generally formed in a layer from approximately 820 to 1200 m, which was the lowermost ELI in winter and the highest ELI in summer; however, in all seasons, the lowest base height was characteristic of daytime inversions. Both surface-based and elevated inversion layers were distinguished by comparable thicknesses, particularly for those occurring at night-time (generally within the range of 150-200 m). From November to March, greater thicknesses were identified in ELIs with lower occurrences, whereas SBIs were identified in the remaining months of the year.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Temporal structure of thermal inversions in Łeba (Poland)

Czarnecka

Nidzgorska-Lencewicz

Rawicki

2018

Theor Appl Climatol

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“…The nighttime stably-stratified layer near the ground reduces the vertical momentum exchange, thus decoupling it from the flow above and causing decreased wind speeds. The overlying wind speed increases because of the inhibited transfer of momentum to the lower stable layer (Brümmer and Schultze 2015). During daytime unstable conditions the vertical exchange of momentum is significant throughout the depth of the boundary layer.…”

Section: Weibull Distribution and Reversal Heightmentioning

confidence: 97%

“…The meteorological facility is installed at the broadcasting tower of the Norddeutscher Rundfunk (NDR) at the eastern edge of Hamburg (53.5192 • N, 10.1029 • E) at a distance of about 8 km from the city centre. The Hamburg weather mast facility is described in detail in Brümmer et al (2012) and Brümmer and Schultze (2015), thus, we give only a short description here. The entire facility consists of two parts: a 12-m mast and the main broadcasting mast; they are about 170 m apart.…”

Section: Hamburg (Suburban)mentioning

confidence: 99%

Weibull Wind-Speed Distribution Parameters Derived from a Combination of Wind-Lidar and Tall-Mast Measurements Over Land, Coastal and Marine Sites

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Floors

Peña

et al. 2015

Boundary-Layer Meteorol

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Wind-speed observations from tall towers are used in combination with observations up to 600 m in altitude from a Doppler wind lidar to study the long-term conditions over suburban (Hamburg), rural coastal (Høvsøre) and marine (FINO3) sites. The variability in the wind field among the sites is expressed in terms of mean wind speed and Weibull distribution shape-parameter profiles. The consequences of the carrier-to-noise-ratio (CNR) threshold-value choice on the wind-lidar observations are revealed as follows. When the wind-lidar CNR is lower than a prescribed threshold value, the observations are often filtered out as the uncertainty in the wind-speed measurements increases. For a pulsed heterodyne Doppler lidar, use of the traditional -22 dB CNR threshold value at all measuring levels up to 600 m results in a ≈7 % overestimation in the long-term mean wind speed over land, and a ≈12 % overestimation in coastal and marine environments. In addition, the height of the profile maximum of the shape parameter of the Weibull distribution (so-called reversal height) is found to depend on the applied CNR threshold; it is found to be lower at small CNR threshold values. The reversal height is greater in the suburban (high roughness) than in the rural (low roughness) area. In coastal areas the reversal height is lower than that over land and relates to the internal boundary layer that develops downwind from the coastline. Over the sea the shape parameter increases towards the sea surface. A parametrization of the vertical profile of the shape parameter fits well with observations over land, coastal regions and over the sea. An applied model for the dependence of the reversal height on the surface roughness is in good agreement with the observations over land.

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Trends in temperature and wind speed from 40 years of observations at a 200‐m high meteorological tower in Southwest Germany

Köhler

Vüllers

Kalthoff

2017

Intl Journal of Climatology

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Forty years of temperature and wind measurements at Karlsruhe Institute of Technology's 200-m high meteorological tower in the Upper Rhine Valley in Southwest Germany are used to calculate trends in the mixed and residual layer respectively, which can be compared to trends in the surface layer. For trend analysis, the Mann-Kendall test is used. Data are analysed on an annual, seasonal, and daily scale. For the variable temperature, a significant positive annual trend is found. Seasonally, the strongest temperature increases are observed in spring and summer. This is also reflected by significant positive trends for meteorological indices such as summer days, tropical days, and growing season length. On a daily scale, the strongest temperature increase is found in the mixed layer during nighttime. This results in a stronger stable stratification and in a higher number of surface inversions. Wind speed measurements reveal a significant negative annual trend in the mixed layer at a height of 200 m. Seasonally, weakly negative trends are found for spring and summer. It can be shown that the trends for wind speed are only partly be related to modifications of surface roughness in the vicinity of the site.

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Analysis of a 7-year low-level temperature inversion data set measured at the 280 m high Hamburg weather mast

Cited by 24 publications

References 0 publications

Temporal structure of thermal inversions in Łeba (Poland)

Temporal structure of thermal inversions in Łeba (Poland)

Weibull Wind-Speed Distribution Parameters Derived from a Combination of Wind-Lidar and Tall-Mast Measurements Over Land, Coastal and Marine Sites

Trends in temperature and wind speed from 40 years of observations at a 200‐m high meteorological tower in Southwest Germany

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