scholarly journals Measurement of wind profiles by motion-stabilised ship-borne Doppler lidar

2015 ◽  
Vol 8 (11) ◽  
pp. 4993-5007 ◽  
Author(s):  
P. Achtert ◽  
I. M. Brooks ◽  
B. J. Brooks ◽  
B. I. Moat ◽  
J. Prytherch ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Wind Direction ◽  
Open Water ◽  
The Arctic ◽  
Doppler Lidar ◽  
Wind Speeds ◽  
Custom Made ◽  
Wind Profiles ◽  
Vertical Winds

Abstract. Three months of Doppler lidar wind measurements were obtained during the Arctic Cloud Summer Experiment on the icebreaker Oden during the summer of 2014. Such ship-borne Doppler measurements require active stabilisation to remove the effects of ship motion. We demonstrate that the combination of a commercial Doppler lidar with a custom-made motion-stabilisation platform enables the retrieval of wind profiles in the Arctic atmospheric boundary layer during both cruising and ice-breaking with statistical uncertainties comparable to land-based measurements. This held true particularly within the atmospheric boundary layer even though the overall aerosol load was very low. Motion stabilisation was successful for high wind speeds in open water and the resulting wave conditions. It allows for the retrieval of vertical winds with a random error below 0.2 m s−1. The comparison of lidar-measured wind and radio soundings gives a mean bias of 0.3 m s−1 (2°) and a mean standard deviation of 1.1 m s−1 (12°) for wind speed (wind direction). The agreement for wind direction degrades with height. The combination of a motion-stabilised platform with a low-maintenance autonomous Doppler lidar has the potential to enable continuous long-term high-resolution ship-based wind profile measurements over the oceans.

scholarly journals Measurement of wind profiles by motion-stabilised ship-borne Doppler lidar

2015 ◽  
Vol 8 (9) ◽  
pp. 9339-9372 ◽  
Author(s):  
P. Achtert ◽  
I. M. Brooks ◽  
B. J. Brooks ◽  
B. I. Moat ◽  
J. Prytherch ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Open Water ◽  
The Arctic ◽  
Doppler Lidar ◽  
Arctic Boundary Layer ◽  
Wind Speeds ◽  
Custom Made ◽  
Wind Measurements ◽  
Wind Profiles

Abstract. Three months of Doppler lidar wind measurements were obtained during the Arctic Cloud Summer Experiment on the icebreaker Oden during the summer of 2014. Such ship-borne measurements require active stabilisation to remove the effects of ship motion. We demonstrate that the combination of a commercial Doppler lidar with a custom-made motion-stabilisation platform enables the retrieval of wind profiles in the Arctic boundary layer during both cruising and ice-breaking with statistical uncertainties comparable to land-based measurements. This holds particularly within the planetary boundary layer even though the overall aerosol load was very low. Motion stabilisation was successful for high wind speeds in open water and the resulting wave conditions. It allows for the retrieval of winds with a random error below 0.2 m s−1, comparable to the measurement error of standard radiosondes. The combination of a motion-stabilised platform with a low-maintenance autonomous Doppler lidar has the potential to enable continuous long-term high-resolution ship-based wind profile measurements over the oceans.

scholarly journals Shipborne wind measurement and motion-induced error correction by coherent doppler lidar over yellow sea in 2014

2018 ◽  
Vol 176 ◽  
pp. 06014
Author(s):  
Xiaochun Zhai ◽  
Songhua Wu ◽  
Bingyi Liu ◽  
Xiaoquan Song
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Error Correction ◽  
Yellow Sea ◽  
Doppler Lidar ◽  
Marine Atmospheric Boundary Layer ◽  
Wind Measurement ◽  
Coherent Doppler Lidar ◽  
Wind Profiles ◽  
Correction System

Shipborne wind observations by the Coherent Doppler Lidar (CDL) during the 2014 Yellow Sea campaign are presented to study the structure of the Marine Atmospheric Boundary Layer (MABL). This paper gives an analysis of the correction for horizontal and vertical wind measurement, demonstrating that the combination of the CDL with the attitude correction system enables the retrieval of wind profiles in the MABL during both anchored and cruising measurement with satisfied statistical uncertainties.

scholarly journals Analysis of the performance of a ship-borne scanning wind lidar in the Arctic and Antarctic

2018 ◽  
Author(s):  
Rolf Zentek ◽  
Svenja H. E. Kohnemann ◽  
Günther Heinemann
Keyword(s):  
Boundary Layer ◽  
Quality Control ◽  
Wind Speed ◽  
Atmospheric Boundary Layer ◽  
Temporal Resolution ◽  
The Arctic ◽  
High Temporal Resolution ◽  
Doppler Lidar ◽  
Individual Measurement ◽  
Lidar Measurements

Abstract. Profiles of wind speed and direction at high spatial and temporal resolution are fundamental meteorological quantities for studies of the atmospheric boundary layer. Ship-based Doppler lidar measurements can contribute to fill the data gap over oceans particularly in polar regions. In the present study a non-motion stabilized scanning Doppler lidar was operated on board of RV Polarstern in the Arctic (June 2014) and Antarctic (December–January 2015/2016). This is the first time that such a system measured on an icebreaker in the Antarctic. A method for a motion correction of the data in the post-processing is presented. The wind calculation is based on vertical azimuth display (VAD) scans with eight directions that pass a quality control. Additionally a method for an empirical signal-to-noise ratio (SNR) threshold is presented, which can be calculated for individual measurement setups. Lidar wind profiles are compared to total of about 120 radiosonde profiles and also to wind measurements of the ship. The performance of the lidar measurements in comparison with radio soundings shows generally small RMSD (bias) for wind speed of around 1 m s−1 (0.1 m s−1) and for wind direction of around 12° (6°). The postprocessing of the non-motion stabilized data shows a comparable good quality as studies with motion stabilized systems. Two case studies show that a flexible change of SNR can be beneficial for special situations. Further the studies reveal that short-lived Low-Level Jets in the atmospheric boundary layer can be captured by lidar measurements with a high temporal resolution in contrast to routine radio soundings. The present study shows that a non-motion stabilized Doppler lidar can be operated successfully on an icebreaker. It presents a processing chain including quality control tests and error quantification, which is useful for further measurement campaigns.

Study of Thermal Activity in The Mixing Layer During First Generated Single Cloud by Using Combined Observation From Boundary Layer Radar, Doppler Lidar and Time Lapse Camera 

2021 ◽  
Author(s):  
Ginaldi Ari Nugroho ◽  
Kosei Yamaguchi ◽  
Eiichi Nakakita ◽  
Masayuki K. Yamamoto ◽  
Seiji Kawamura ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Time Series ◽  
Atmospheric Boundary Layer ◽  
Vertical Velocity ◽  
Time Lapse ◽  
Small Scale ◽  
Thermal Activity ◽  
Doppler Lidar ◽  
Cumulus Cloud ◽  
Scale Perturbation

<p>Detailed observation of small scale perturbation in the atmospheric boundary layer during the first generated cumulus cloud are conducted. Our target is to study this small scale perturbation, especially related to the thermal activity at the first generated cumulus cloud. The observation is performed during the daytime on August 17, 2018, and September 03, 2018. Location is focused in the urban area of Kobe, Japan. High-resolution instruments such as Boundary Layer Radar, Doppler Lidar, and Time Lapse camera are used in this observation. Boundary Layer Radar, and Doppler Lidar are used for clear air observation. Meanwhile Time Lapse Camera are used for cloud existence observation. The atmospheric boundary layer structure is analyzed based on vertical velocity profile, variance, skewness, and estimated atmospheric boundary layer height. Wavelet are used to observe more of the period of the thermal activity. Furthermore, time correlation between vertical velocity time series from height 0.3 to 2 km and image pixel of generated cloud time series are also discussed in this study.</p>

scholarly journals STRUCTURE OF TURBULENCE IN THE URBAN ATMOSPHERIC BOUNDARY LAYER DETECTED IN THE DOPPLER LIDAR OBSERVATION

2011 ◽  
Vol 67 (4) ◽  
pp. I_313-I_318 ◽  
Author(s):  
Ryoko ODA ◽  
Hironori IWAI ◽  
Shoken ISHII ◽  
Shinya SEKIZAWA ◽  
Kohei MIZUTANI ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Doppler Lidar ◽  
Lidar Observation

scholarly journals Wind profile correction algorithm based on Atmospheric Boundary Layer stability profile

2021 ◽  
Author(s):  
Francisco Albuquerque Neto ◽  
Vinicius Almeida ◽  
Julia Carelli
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Wind Profile ◽  
Horizontal Wind ◽  
Boundary Layer Stability ◽  
Correction Algorithm ◽  
Horizontal Wind Speed ◽  
Study Region ◽  
Profile Correction ◽  
Wind Profiles

<p>In recent years, the use of radar wind profilers (RWP) at airports has grown significantly with the aim of supporting decision makers to maintain the safety of aircraft landings and takeoffs.</p><p>The RWP provide vertical profiles of averaged horizontal wind speed and direction and vertical wind velocity for the entire Atmospheric Boundary Layer (ABL) and beyond. In addition, RWP with Radio-Acoustic Sounding System (RASS) are able to retrieve virtual temperature profiles in the ABL.</p><p>RWP data evaluation is usually based on the so-called Doppler Beam Swinging method (DBS) which assumes homogeneity and stationarity of the wind field. Often, transient eddies violate this homogeneity and stationarity requirement. Hence, incorrect wind profiles can relate to transient eddies and present a problem for the forecast of high-impact weather phenomena in airports. This work intends to provide a method for removing outliers in such profiles based on historical data and other variables related to the Atmospheric Boundary Layer stability profile in the study region.</p><p>For this study, a dataset of almost one year retrieved from a RWP LAP3000 with RASS Extension is used for a wind profile correction algorithm development.</p><p>The algorithm consists of the detection of outliers in the wind profiles based on the thermodynamic structure of the ABL and the generation of the corrected profiles.</p><p>Results show that the algorithm is capable of identifying and correcting unrealistic variations in speed caused by transient eddies. The method can be applied as a complement to the RWP data processing for better data reliability.</p><p> </p><p>Keywords: atmospheric boundary layer; stability profile; wind profile</p>

scholarly journals Stable Atmospheric Boundary Layers and Diurnal Cycles: Challenges for Weather and Climate Models

2013 ◽  
Vol 94 (11) ◽  
pp. 1691-1706 ◽  
Author(s):  
A. A. M. Holtslag ◽  
G. Svensson ◽  
P. Baas ◽  
S. Basu ◽  
B. Beare ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Atmospheric Boundary Layer ◽  
Climate Models ◽  
Model Performance ◽  
Weather Forecast ◽  
The Arctic ◽  
Diurnal Cycles ◽  
Low Wind Speed ◽  
Weather And Climate

The representation of the atmospheric boundary layer is an important part of weather and climate models and impacts many applications such as air quality and wind energy. Over the years, the performance in modeling 2-m temperature and 10-m wind speed has improved but errors are still significant. This is in particular the case under clear skies and low wind speed conditions at night as well as during winter in stably stratified conditions over land and ice. In this paper, the authors review these issues and provide an overview of the current understanding and model performance. Results from weather forecast and climate models are used to illustrate the state of the art as well as findings and recommendations from three intercomparison studies held within the Global Energy and Water Exchanges (GEWEX) Atmospheric Boundary Layer Study (GABLS). Within GABLS, the focus has been on the examination of the representation of the stable boundary layer and the diurnal cycle over land in clear-sky conditions. For this purpose, single-column versions of weather and climate models have been compared with observations, research models, and large-eddy simulations. The intercomparison cases are based on observations taken in the Arctic, Kansas, and Cabauw in the Netherlands. From these studies, we find that even for the noncloudy boundary layer important parameterization challenges remain.

scholarly journals Unmanned Aerial Systems for Investigating the Polar Atmospheric Boundary Layer—Technical Challenges and Examples of Applications

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 416 ◽  
Author(s):  
Astrid Lampert ◽  
Barbara Altstädter ◽  
Konrad Bärfuss ◽  
Lutz Bretschneider ◽  
Jesper Sandgaard ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Low Temperatures ◽  
Open Water ◽  
Future Research ◽  
Small Scale ◽  
Unmanned Aerial Systems ◽  
Research Activities ◽  
Aerial Systems ◽  
The Impact

Unmanned aerial systems (UAS) fill a gap in high-resolution observations of meteorological parameters on small scales in the atmospheric boundary layer (ABL). Especially in the remote polar areas, there is a strong need for such detailed observations with different research foci. In this study, three systems are presented which have been adapted to the particular needs for operating in harsh polar environments: The fixed-wing aircraft M 2 AV with a mass of 6 kg, the quadrocopter ALICE with a mass of 19 kg, and the fixed-wing aircraft ALADINA with a mass of almost 25 kg. For all three systems, their particular modifications for polar operations are documented, in particular the insulation and heating requirements for low temperatures. Each system has completed meteorological observations under challenging conditions, including take-off and landing on the ice surface, low temperatures (down to −28 ∘ C), icing, and, for the quadrocopter, under the impact of the rotor downwash. The influence on the measured parameters is addressed here in the form of numerical simulations and spectral data analysis. Furthermore, results from several case studies are discussed: With the M 2 AV, low-level flights above leads in Antarctic sea ice were performed to study the impact of areas of open water within ice surfaces on the ABL, and a comparison with simulations was performed. ALICE was used to study the small-scale structure and short-term variability of the ABL during a cruise of RV Polarstern to the 79 ∘ N glacier in Greenland. With ALADINA, aerosol measurements of different size classes were performed in Ny-Ålesund, Svalbard, in highly complex terrain. In particular, very small, freshly formed particles are difficult to monitor and require the active control of temperature inside the instruments. The main aim of the article is to demonstrate the potential of UAS for ABL studies in polar environments, and to provide practical advice for future research activities with similar systems.

scholarly journals A parameter model of gas exchange for the seasonal sea ice zone

Ocean Science ◽  
2014 ◽  
Vol 10 (1) ◽  
pp. 17-28 ◽  
Author(s):  
B. Loose ◽  
W. R. McGillis ◽  
D. Perovich ◽  
C. J. Zappa ◽  
P. Schlosser
Keyword(s):  
Boundary Layer ◽  
Gas Exchange ◽  
Sea Ice ◽  
Open Water ◽  
Field Studies ◽  
The Arctic ◽  
Gas Transfer ◽  
Transfer Velocity ◽  
Using Data ◽  
Effective Transfer

Abstract. Carbon budgets for the polar oceans require better constraint on air–sea gas exchange in the sea ice zone (SIZ). Here, we utilize advances in the theory of turbulence, mixing and air–sea flux in the ice–ocean boundary layer (IOBL) to formulate a simple model for gas exchange when the surface ocean is partially covered by sea ice. The gas transfer velocity (k) is related to shear-driven and convection-driven turbulence in the aqueous mass boundary layer, and to the mean-squared wave slope at the air–sea interface. We use the model to estimate k along the drift track of ice-tethered profilers (ITPs) in the Arctic. Individual estimates of daily-averaged k from ITP drifts ranged between 1.1 and 22 m d−1, and the fraction of open water (f) ranged from 0 to 0.83. Converted to area-weighted effective transfer velocities (keff), the minimum value of keff was 10−55 m d−1 near f = 0 with values exceeding keff = 5 m d−1 at f = 0.4. The model indicates that effects from shear and convection in the sea ice zone contribute an additional 40% to the magnitude of keff, beyond what would be predicted from an estimate of keff based solely upon a wind speed parameterization. Although the ultimate scaling relationship for gas exchange in the sea ice zone will require validation in laboratory and field studies, the basic parameter model described here demonstrates that it is feasible to formulate estimates of k based upon properties of the IOBL using data sources that presently exist.

scholarly journals Finescale Clusterization Intermittency of Turbulence in the Atmospheric Boundary Layer

2020 ◽  
Vol 77 (7) ◽  
pp. 2375-2392
Author(s):  
Lei Liu ◽  
Fei Hu
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Return Time ◽  
Statistical Simulation ◽  
Convective Boundary ◽  
Wind Speeds ◽  
Stable Conditions ◽  
Telegraphic Approximation ◽  
Better Than

AbstractThe intermittency of atmospheric turbulence plays an important role in the understanding of particle dispersal in the atmospheric boundary layer and in the statistical simulation of high-frequency wind speed in various applications. There are two kinds of intermittency, namely, the magnitude intermittency (MI) related to non-Gaussianity and the less studied clusterization intermittency (CI) related to long-term correlation. In this paper, we use a 20 Hz ultrasonic dataset lasting for 1 month to study CI of turbulent velocity fluctuations at different scales. Basing on the analysis of return-time distribution of telegraphic approximation series, we propose to use the shape parameter of the Weibull distribution to measure CI. Observations of this parameter show that contrary to MI, CI tends to weaken as the scale increases. Besides, significant diurnal variations, showing that CI tends to strengthen during the daytime (under unstable conditions) and weaken during the nighttime (under stable conditions), are found at different observation heights. In the convective boundary layer, the mixed-layer similarity is found to scale the CI exponent better than the Monin–Obukhov similarity. At night, CI is found to vary less with height in the regime with large mean wind speeds than in the regime with small mean wind speeds, according to the hockey-stick theory.

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