Temperature profiles with bi-static Doppler-RASS and their correction

Abstract. The technique of atmospheric temperature profiling by Doppler-RASS is discussed. The set up with bi-static (separated transmit and receiving) antennas implies a range dependent scattering angle. The retrieval scheme developed by Kon for such antenna geometry is reviewed and its limits of validity are discussed. Empirical tuning of the effective antenna aperture is proposed to fit the retrieved temperature profiles to reality. The method is based on the assumption that potential temperature profiles under presumedly neutral conditions are constant with height. Examples of application of the measuring technique for atmospheric boundary layer characterization are presented.

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Temperature profiles with bi-static Doppler-RASS and their accuracy

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-5-1075-2012 ◽

2012 ◽

Vol 5 (1) ◽

pp. 1075-1100

Author(s):

B. Hennemuth ◽

G. Peters ◽

H.-J. Kirtzel

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Atmospheric Temperature ◽

Measuring Technique ◽

Temperature Profiles ◽

Antenna Aperture ◽

Scattering Angle ◽

Retrieval Scheme ◽

Set Up

Abstract. The technique of atmospheric temperature profiling by Doppler-RASS is discussed. The set up with bi-static (separated transmit and receiving) antennas implies a range dependent scattering angle. The retrieval scheme developed by Kon for such antenna geometry is reviewed and its limits of validity are discussed. Empirical tuning of the efficient antenna aperture is proposed to fit the retrieved temperature profiles to reality. Examples of application of the measuring technique for atmospheric boundary layer characterization are presented.

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Inference of Marine Atmospheric Boundary Layer Moisture and Temperature Structure Using Airborne Lidar and Infrared Radiometer Data

Journal of Applied Meteorology ◽

10.1175/1520-0450-37.3.308 ◽

1998 ◽

Vol 37 (3) ◽

pp. 308-324 ◽

Cited By ~ 10

Author(s):

Stephen P. Palm ◽

Denise Hagan ◽

Geary Schwemmer ◽

S. H. Melfi

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Potential Temperature ◽

Airborne Lidar ◽

Temperature Structure ◽

Marine Atmospheric Boundary Layer ◽

Space Technology ◽

Near Surface ◽

Surface Moisture ◽

Infrared Radiometer

Abstract A new technique for retrieving near-surface moisture and profiles of mixing ratio and potential temperature through the depth of the marine atmospheric boundary layer (MABL) using airborne lidar and multichannel infrared radiometer data is presented. Data gathered during an extended field campaign over the Atlantic Ocean in support of the Lidar In-space Technology Experiment are used to generate 16 moisture and temperature retrievals that are then compared with dropsonde measurements. The technique utilizes lidar-derived statistics on the height of cumulus clouds that frequently cap the MABL to estimate the lifting condensation level. Combining this information with radiometer-derived sea surface temperature measurements, an estimate of the near-surface moisture can be obtained to an accuracy of about 0.8 g kg−1. Lidar-derived statistics on convective plume height and coverage within the MABL are then used to infer the profiles of potential temperature and moisture with a vertical resolution of 20 m. The rms accuracy of derived MABL average moisture and potential temperature is better than 1 g kg−1 and 1°C, respectively. The method relies on the presence of a cumulus-capped MABL, and it was found that the conditions necessary for use of the technique occurred roughly 75% of the time. The synergy of simple aerosol backscatter lidar and infrared radiometer data also shows promise for the retrieval of MABL moisture and temperature from space.

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How is the marine atmospheric boundary layer turbulence organized in the trades ?

10.5194/egusphere-egu21-12339 ◽

2021 ◽

Author(s):

Pierre-Etienne Brilouet ◽

Marie Lothon ◽

Sandrine Bony

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Vertical Velocity ◽

Large Scale ◽

Layer Structure ◽

Potential Temperature ◽

Surface Wind ◽

Cloud Amount ◽

Velocity Spectrum ◽

Marine Atmospheric Boundary Layer

Tradewind clouds can exhibit a wide diversity of mesoscale organizations, and the turbulence of marine atmospheric boundary layer (MABL) can exhibit coherent structures and mesoscale circulations. One of the objectives of the EUREC4A (Elucidating the role of cloud-circulation coupling in climate) field experiment was to better understand the tight interplay between the mesoscale organization of clouds, boundary-layer processes, and the large-scale environment.During the experiment, that took place East of Barbados over the Western Tropical Atlantic Ocean in Jan-Feb 2020, the French ATR-42 research aircraft was devoted to the characterization of the cloud amount and of the subcoud layer structure. During its 17 research flights, it sampled a large diversity of large scale conditions and cloud patterns. Multiple sensors onboard the aircraft measured high-frequency fluctuations of potential temperature, water vapour mixing ratio and wind , allowing for an extensive characterization of the turbulence within the subcloud layer. A quality-controled and calibrated turbulence dataset was produced on the basis of these measurements, which is now available on the EUREC4A AERIS data portal.The MABL turbulent structure is studied using this dataset, through a spectral analysis of the vertical velocity. Vertical profiles of characteristic length scales reveal a non-isotropic structure with a stretching of the eddies along the mean wind. The organization strength of the turbulent field is also explored by defining a diagnostic based on the shape of the vertical velocity spectrum. The structure and the degree of organization of the subcloud layer are characterized for different types of mesoscale convective pattern and as a function of the large-scale environment, including near-surface wind and lower-tropospheric stability conditions.&#160;

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Operational profiling of temperature using ground-based microwave radiometry at Payerne: prospects and challenges

Atmospheric Measurement Techniques ◽

10.5194/amt-5-1121-2012 ◽

2012 ◽

Vol 5 (5) ◽

pp. 1121-1134 ◽

Cited By ~ 78

Author(s):

U. Löhnert ◽

O. Maier

Keyword(s):

Boundary Layer ◽

Data Quality ◽

Microwave Radiometer ◽

Lower Boundary ◽

Weather Conditions ◽

Atmospheric Temperature ◽

Temperature Profiles ◽

Data Quality Control ◽

Time Period ◽

Lower Boundary Layer

Abstract. The motivation of this study is to verify theoretical expectations placed on ground-based microwave radiometer (MWR) techniques and to confirm whether they are suitable for supporting key missions of national weather services, such as timely and accurate weather advisories and warnings. We evaluate reliability and accuracy of atmospheric temperature profiles retrieved continuously by the microwave profiler system HATPRO (Humidity And Temperature PROfiler) operated at the aerological station of Payerne (MeteoSwiss) in the time period August 2006–December 2009. Assessment is performed by comparing temperatures from the radiometer against temperature measurements from a radiosonde accounting for a total of 2107 quality-controlled all-season cases. In the evaluated time period, the MWR delivered reliable temperature profiles in 86% of all-weather conditions on a temporal resolution of 12–13 min. Random differences between MWR and radiosonde are down to 0.5 K in the lower boundary layer and increase to 1.7 K at 4 km height. The differences observed between MWR and radiosonde in the lower boundary layer are similar to the differences observed between the radiosonde and another in-situ sensor located on a close-by 30 m tower. Temperature retrievals from above 4 km contain less than 5% of the total information content of the measurements, which makes clear that this technique is mainly suited for continuous observations in the boundary layer. Systematic temperature differences are also observed throughout the retrieved profile and can account for up to ±0.5 K. These errors are due to offsets in the measurements of the microwave radiances that have been corrected for in data post-processing and lead to nearly bias-free overall temperature retrievals. Different reasons for the radiance offsets are discussed, but cannot be unambiguously determined retrospectively. Monitoring and, if necessary, corrections for radiance offsets as well as a real-time rigorous automated data quality control are mandatory for microwave profiler systems that are designated for operational temperature profiling. In the analysis of a subset of different atmospheric situations, it is shown that lifted inversions and data quality during precipitation present the largest challenges for operational MWR temperature profiling.

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Assessing the potential of passive microwave radiometers for continuous temperature profile retrieval using a three year data set from Payerne

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-4-7435-2011 ◽

2011 ◽

Vol 4 (6) ◽

pp. 7435-7469 ◽

Cited By ~ 2

Author(s):

U. Löhnert ◽

O. Maier

Keyword(s):

Boundary Layer ◽

Lower Boundary ◽

Weather Conditions ◽

Atmospheric Temperature ◽

Temperature Measurements ◽

Temperature Profiles ◽

Data Quality Control ◽

Data Set ◽

Time Period ◽

Lower Boundary Layer

Abstract. The motivation of this study is to verify theoretical expectations placed on ground-based radiometer techniques and to confirm whether they are suitable for supporting key missions of national weather services, such as timely and accurate weather advisories and warnings. We evaluate reliability and accuracy of atmospheric temperature profiles retrieved continuously by a HATPRO (Humidity And Temperature PROfiler) system operated at the aerological station of Payerne (MeteoSwiss) in the time period August 2006–December 2009. Assessment is performed by comparing temperatures from the radiometer against temperature measurements from a radiosonde accounting for a total of 2088 quality-controlled all-season cases. In the evaluated time period, HATPRO delivered reliable temperature profiles in 88% of all-weather conditions with a temporal resolution of 15 min. Random differences between HATPRO and radiosonde are down to 0.5 K in the lower boundary layer and rise up to 1.7 K at 4 km height. The differences observed between HATPRO and radiosonde in the lower boundary layer are similar to the differences observed between the radiosonde and another in-situ sensor located on a close-by 30 m tower. Temperature retrievals from above 4 km contain less than 5% of the total information content of the measurements, which makes clear that this technique is mainly suited for continuous observations in the boundary layer. Systematic temperature differences are also observed throughout the retrieved profile and can account for up to ±0.5 K. These errors are due to offsets in the measurements of the microwave radiances that have been corrected for in data post-processing and lead to nearly bias-free overall temperature retrievals. Different reasons for the radiance offsets are discussed, but cannot be unambiguously determined retrospectively. Monitoring and, if necessary, corrections for radiance offsets as well as a real-time rigorous automated data quality control are mandatory for microwave profiler systems that are designated for operational temperature profiling. In the analysis of day/night differences, it is shown that systematic differences between radiosonde and HATPRO decrease throughout the boundary layer if 2 m surface temperature measurements are included in the retrieval.

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Validation of atmospheric boundary layer turbulence model by on-site measurements

Thermal Science ◽

10.2298/tsci1001199s ◽

2010 ◽

Vol 14 (1) ◽

pp. 199-207 ◽

Cited By ~ 1

Author(s):

Zarko Stevanovic ◽

Nikola Mirkov ◽

Zana Stevanovic ◽

Andrijana Stojanovic

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Linear Models ◽

Stokes Equations ◽

Turbulence Models ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Boundary Layer Turbulence ◽

Askervein Hill ◽

Neutral Conditions

Modeling atmosperic boundary layer with standard linear models does not sufficiently reproduce wind conditions in complex terrain, especially on leeward sides of terrain slopes. More complex models, based on Reynolds averaged Navier-Stokes equations and two-equation k-? turbulence models for neutral conditions in atmospheric boundary layer, written in general curvilinear non-orthogonal co-ordinate system, have been evaluated. In order to quantify the differences and level of accuracy of different turbulence models, investigation has been performed using standard k-? model without additional production terms and k-? turbulence models with modified set of model coefficients. The sets of full conservation equations are numerically solved by computational fluid dynamics technique. Numerical calculations of turbulence models are compared to the reference experimental data of Askervein hill measurements.

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Atmospheric boundary layer dynamics from balloon soundings worldwide: CLASS4GL v1.0

Geoscientific Model Development ◽

10.5194/gmd-12-2139-2019 ◽

2019 ◽

Vol 12 (5) ◽

pp. 2139-2153 ◽

Cited By ~ 4

Author(s):

Hendrik Wouters ◽

Irina Y. Petrova ◽

Chiel C. van Heerwaarden ◽

Jordi Vilà-Guerau de Arellano ◽

Adriaan J. Teuling ◽

...

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Mixed Layer ◽

Weather Prediction ◽

Potential Temperature ◽

Specific Humidity ◽

Weather Extremes ◽

Coupled Models ◽

Layer Height ◽

Mixed Layer Height

Abstract. The coupling between soil, vegetation and atmosphere is thought to be crucial in the development and intensification of weather extremes, especially meteorological droughts, heat waves and severe storms. Therefore, understanding the evolution of the atmospheric boundary layer (ABL) and the role of land–atmosphere feedbacks is necessary for earlier warnings, better climate projection and timely societal adaptation. However, this understanding is hampered by the difficulties of attributing cause–effect relationships from complex coupled models and the irregular space–time distribution of in situ observations of the land–atmosphere system. As such, there is a need for simple deterministic appraisals that systematically discriminate land–atmosphere interactions from observed weather phenomena over large domains and climatological time spans. Here, we present a new interactive data platform to study the behavior of the ABL and land–atmosphere interactions based on worldwide weather balloon soundings and an ABL model. This software tool – referred to as CLASS4GL (http://class4gl.eu, last access: 27 May 2018) – is developed with the objectives of (a) mining appropriate global observational data from ∼15 million weather balloon soundings since 1981 and combining them with satellite and reanalysis data and (b) constraining and initializing a numerical model of the daytime evolution of the ABL that serves as a tool to interpret these observations mechanistically and deterministically. As a result, it fully automizes extensive global model experiments to assess the effects of land and atmospheric conditions on the ABL evolution as observed in different climate regions around the world. The suitability of the set of observations, model formulations and global parameters employed by CLASS4GL is extensively validated. In most cases, the framework is able to realistically reproduce the observed daytime response of the mixed-layer height, potential temperature and specific humidity from the balloon soundings. In this extensive global validation exercise, a bias of 10.1 m h−1, −0.036 K h−1 and 0.06 g kg−1 h−1 is found for the morning-to-afternoon evolution of the mixed-layer height, potential temperature and specific humidity. The virtual tool is in continuous development and aims to foster a better process understanding of the drivers of the ABL evolution and their global distribution, particularly during the onset and amplification of weather extremes. Finally, it can also be used to scrutinize the representation of land–atmosphere feedbacks and ABL dynamics in Earth system models, numerical weather prediction models, atmospheric reanalysis and satellite retrievals, with the ultimate goal of improving local climate projections, providing earlier warning of extreme weather and fostering a more effective development of climate adaptation strategies. The tool can be easily downloaded via http://class4gl.eu (last access: 27 May 2018) and is open source.

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Atmospheric boundary layer dynamics from balloon soundings worldwide: CLASS4GL v1.0

10.5194/gmd-2019-24 ◽

2019 ◽

Author(s):

Hendrik Wouters ◽

Irina Y. Petrova ◽

Chiel C. van Heerwaarden ◽

Jordi Vilà-Guerau de Arellano ◽

Adriaan J. Teuling ◽

...

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Prediction Models ◽

Climate Adaptation ◽

Weather Prediction ◽

Potential Temperature ◽

Specific Humidity ◽

Climate Projections ◽

Weather Extremes ◽

Coupled Models

Abstract. The coupling between soil, vegetation and atmosphere is thought to be crucial in the development and intensification of weather extremes, especially meteorological droughts, heatwaves and severe storms. Therefore, understanding evolution of the atmospheric boundary layer (ABL) and the role of land–atmosphere feedbacks is necessary for earlier warnings, better climate projection and timely societal adaptation. However, this understanding is hampered by the difficulties to attribute cause–effect relationships from complex coupled models, and the irregular space–time distribution of in situ observations of the land–atmosphere system. As such, there is a need for simple deterministic appraisals that systematically discriminate land–atmosphere interactions from observed weather phenomena over large domains and climatological time spans. Here, we present a new interactive data platform to study the behaviour of the ABL and land–atmosphere interactions based on worldwide weather balloon soundings and an ABL model. This software tool – referred to as CLASS4GL (http://class4gl.eu) – is developed with the objectives to (a) mine appropriate global observational data from over 2 million weather balloon soundings since 1981 and combine them with satellite and reanalysis data, and (b) constrain and initialize a numerical model of the daytime evolution of the ABL that serves as a tool to interpret these observations mechanistically and deterministically. As a result, it fully automises extensive global model experiments to assess the effects of land and atmospheric conditions on the ABL evolution as observed in different climate regions around the world. The suitability of the set of observations, model formulations and global parameters employed by CLASS4GL is extensively validated. In most cases, the framework is able to realistically reproduce the observed daytime response of the ABL height, potential temperature and specific humidity from the balloon soundings. In this extensive global validation exercise, a bias of 0.2 m h−1, −0.052 K h−1 and 0.07 g kg−1 h−1 is found for the morning-to-afternoon evolution of the ABL height, potential temperature and specific humidity. The virtual tool is in continuous development, and aims to foster a better process-understanding of the drivers of the ABL evolution and their global distribution, particularly during the onset and amplification of weather extremes. Finally, it can also be used to scrutinize the representation of land–atmosphere feedbacks and ABL dynamics in Earth system models, numerical weather prediction models, atmospheric reanalysis, and satellite retrievals, with the ultimate goal to improve local climate projections, provide earlier warning of extreme weather, and foster a more effective development of climate adaptation strategies. The tool can be easily downloaded via http://class4gl.eu and is open source.

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Fiber optic distributed temperature sensing for the determination of the nocturnal atmospheric boundary layer height

Atmospheric Measurement Techniques ◽

10.5194/amt-4-143-2011 ◽

2011 ◽

Vol 4 (2) ◽

pp. 143-149 ◽

Cited By ~ 26

Author(s):

C. A. Keller ◽

H. Huwald ◽

M. K. Vollmer ◽

A. Wenger ◽

M. Hill ◽

...

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Fiber Optic ◽

Temperature Inversion ◽

Nocturnal Boundary Layer ◽

Temperature Sensing ◽

Temperature Profiles ◽

Distributed Temperature Sensing ◽

Boundary Layer Height

Abstract. A new method for measuring air temperature profiles in the atmospheric boundary layer at high spatial and temporal resolution is presented. The measurements are based on Raman scattering distributed temperature sensing (DTS) with a fiber optic cable attached to a tethered balloon. These data were used to estimate the height of the stable nocturnal boundary layer. The experiment was successfully deployed during a two-day campaign in September 2009, providing evidence that DTS is well suited for this atmospheric application. Observed stable temperature profiles exhibit an exponential shape confirming similarity concepts of the temperature inversion close to the surface. The atmospheric mixing height (MH) was estimated to vary between 5 m and 50 m as a result of the nocturnal boundary layer evolution. This value is in good agreement with the MH derived from concurrent Radon-222 (222Rn) measurements and in previous studies.

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A Planetary Boundary Layer Height Climatology Derived from ECMWF Reanalysis Data

Journal of Climate ◽

10.1175/jcli-d-12-00385.1 ◽

2013 ◽

Vol 26 (17) ◽

pp. 6575-6590 ◽

Cited By ~ 93

Author(s):

Axel von Engeln ◽

João Teixeira

Keyword(s):

Boundary Layer ◽

Planetary Boundary Layer ◽

Potential Temperature ◽

Vertical Gradient ◽

Atmospheric Temperature ◽

Reanalysis Data ◽

Radiosonde Data ◽

Convective Boundary ◽

Seasonal And Diurnal Variations ◽

Ecmwf Reanalysis

Abstract A planetary boundary layer (PBL) height climatology from ECMWF reanalysis data is generated and analyzed. Different methods are first compared to derive PBL heights from atmospheric temperature, pressure, and relative humidity (RH), which mostly make use of profile gradients, for example, in RH, refractivity, and virtual or potential temperature. Three methods based on the vertical gradient of RH, virtual temperature, and potential temperature were selected for the climatology generation. The RH-based method appears to capture the inversion that caps the convective boundary layer very well as a result of its temperature and humidity dependence, while the temperature-based methods appear to capture the PBL better at high latitudes. A validation of the reanalysis fields with collocated radiosonde data shows generally good agreement in terms of mean PBL height and standard deviation for the RH-based method. The generated ECMWF-based PBL height climatology shows many of the expected climatological features, such as a fairly low PBL height near the west coast of continents where stratus clouds are found and PBL growth as the air is advected over warmer waters toward the tropics along the trade winds. Large seasonal and diurnal variations are primarily found over land. The PBL height can exceed 3 km, mostly over desert areas during the day, although large values can also be found in areas such as the ITCZ. The robustness of the statistics was analyzed by using information on the percentage of outliers. Here in particular, the sea-based PBL was found to be very stable.

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