A New Generation of Ground-Based Mobile Platforms for Active and Passive Profiling of the Boundary Layer

2019 ◽  
Vol 100 (1) ◽  
pp. 137-153 ◽  
Author(s):  
Timothy J. Wagner ◽  
Petra M. Klein ◽  
David D. Turner
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Lower Troposphere ◽  
Mobile Systems ◽  
Lower Atmosphere ◽  
Stream Line ◽  
High Temporal Resolution ◽  
Great Success ◽  
Mobile Platforms ◽  
Atmospheric Phenomena

AbstractMobile systems equipped with remote sensing instruments capable of simultaneous profiling of temperature, moisture, and wind at high temporal resolutions can offer insights into atmospheric phenomena that the operational network cannot. Two recently developed systems, the Space Science and Engineering Center (SSEC) Portable Atmospheric Research Center (SPARC) and the Collaborative Lower Atmosphere Profiling System (CLAMPS), have already experienced great success in characterizing a variety of phenomena. Each system contains an Atmospheric Emitted Radiance Interferometer for thermodynamic profiling and a Halo Photonics Stream Line Doppler wind lidar for kinematic profiles. These instruments are augmented with various in situ and remote sensing instruments to provide a comprehensive assessment of the evolution of the lower troposphere at high temporal resolution (5 min or better). While SPARC and CLAMPS can be deployed independently, the common instrument configuration means that joint deployments with well-coordinated data collection and analysis routines are easily facilitated.In the past several years, SPARC and CLAMPS have participated in numerous field campaigns, which range from mesoscale campaigns that require the rapid deployment and teardown of observing systems to multiweek fixed deployments, providing crucial insights into the behavior of many different atmospheric boundary layer processes while training the next generation of atmospheric scientists. As calls for a nationwide ground-based profiling network continue, SPARC and CLAMPS can play an important role as test beds and prototype nodes for such a network.

scholarly journals A novel post-processing algorithm for Halo Doppler lidars

2019 ◽  
Vol 12 (2) ◽  
pp. 839-852 ◽  
Author(s):  
Ville Vakkari ◽  
Antti J. Manninen ◽  
Ewan J. O'Connor ◽  
Jan H. Schween ◽  
Pieter G. van Zyl ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Radial Velocity ◽  
Planetary Boundary Layer ◽  
Data Availability ◽  
Processing Algorithm ◽  
Stream Line ◽  
Limiting Factor ◽  
High Temporal Resolution ◽  
Post Processing ◽  
Uncertainty Estimates

Abstract. Commercially available Doppler lidars have now been proven to be efficient tools for studying winds and turbulence in the planetary boundary layer. However, in many cases low signal-to-noise ratio is still a limiting factor for utilising measurements by these devices. Here, we present a novel post-processing algorithm for Halo Stream Line Doppler lidars, which enables an improvement in sensitivity of a factor of 5 or more. This algorithm is based on improving the accuracy of the instrumental noise floor and it enables longer integration times or averaging of high temporal resolution data to be used to obtain signals down to −32 dB. While this algorithm does not affect the measured radial velocity, it improves the accuracy of radial velocity uncertainty estimates and consequently the accuracy of retrieved turbulent properties. Field measurements using three different Halo Doppler lidars deployed in Finland, Greece and South Africa demonstrate how the new post-processing algorithm increases data availability for turbulent retrievals in the planetary boundary layer, improves detection of high-altitude cirrus clouds and enables the observation of elevated aerosol layers.

scholarly journals High time resolution boundary layer description using combined remote sensing instruments

2008 ◽  
Vol 26 (9) ◽  
pp. 2597-2612 ◽  
Author(s):  
C. Gaffard ◽  
J. Nash ◽  
E. Walker ◽  
T. J. Hewison ◽  
J. Jones ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Quality Control ◽  
Temporal Resolution ◽  
Lower Troposphere ◽  
High Temporal Resolution ◽  
Wind Profiler ◽  
Sensing Systems ◽  
Atmospheric Profiles ◽  
Remote Sensing Systems ◽  
Observing Systems

Abstract. Ground based remote sensing systems for future observation operations will allow continuous monitoring of the lower troposphere at temporal resolutions much better than every 30 min. Observations which may be considered spurious from an individual instrument can be validated or eliminated when considered in conjunction with measurements from other instruments observing at the same location. Thus, improved quality control of atmospheric profiles from microwave radiometers and wind profilers should be sought by considering the measurements from different systems together rather than individually. In future test bed deployments for future operational observing systems, this should be aided by observations from laser ceilometers and cloud radars. Observations of changes in atmospheric profiles at high temporal resolution in the lower troposphere are presented from a 12 channel microwave radiometer and 1290 MHz UHF wind profiler deployed in southern England during the CSIP field experiment in July/August 2005. The observations chosen were from days when thunderstorms occurred in southern England. Rapid changes near the surface in dry layers are considered, both when rain/hail may be falling from above and where the dry air is associated with cold pools behind organised thunderstorms. Also, short term variations in atmospheric profiles and vertical stability are presented on a day with occasional low cloud, when thunderstorms triggered 50 km down wind of the observing site Improved quality control of the individual remote sensing systems need to be implemented, examining the basic quality of the underlying observations as well as the final outputs, and so for instance eliminating ground clutter as far as possible from the basic Doppler spectra measurements of the wind profiler. In this study, this was performed manually. The potential of incorporating these types of instruments in future upper air observational networks leads to the challenge to improve the observing systems and also to exploit measurements at high temporal resolution in numerical weather prediction. These examples are intended to inform potential operational users of the changes in atmospheric structure that can be observed with the new types of observing system.

scholarly journals Automated ground-based remote sensing measurements of greenhouse gases at the Białystok site in comparison with collocated in situ measurements and model data

2012 ◽  
Vol 12 (15) ◽  
pp. 6741-6755 ◽  
Author(s):  
J. Messerschmidt ◽  
H. Chen ◽  
N. M. Deutscher ◽  
C. Gerbig ◽  
P. Grupe ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Lower Troposphere ◽  
Fourier Transform Spectrometer ◽  
Model Data ◽  
Solar Absorption ◽  
Near Surface ◽  
Tall Tower ◽  
Absorption Measurements

Abstract. The in situ boundary layer measurement site in Białystok (Poland) has been upgraded with a fully automated observatory for total greenhouse gas column measurements. The automated Fourier Transform Spectrometer (FTS) complements the on-site in situ facilities and FTS solar absorption measurements have been recorded nearly continuously in clear and partially cloudy conditions since March 2009. Here, the FTS measurements are compared with the collocated tall tower data. Additionally, simulations of the Jena CO2 inversion model are evaluated with the Białystok measurement facilities. The simulated seasonal CO2 cycle is slightly overestimated by a mean difference of 1.2 ppm ± 0.9 ppm (1σ) in comparison with the FTS measurements. CO2 concentrations at the surface, measured at the tall tower (5 m, 90 m, 300 m), are slightly underestimated by −1.5 ppm, −1.6 ppm, and −0.7 ppm respectively during the day and by −9.1 ppm, −5.9 ppm, and −1.3 ppm during the night. The comparison of the simulated CO2 profiles with low aircraft profiles shows a slight overestimation of the lower troposphere (by up to 1 ppm) and an underestimation in near-surface heights until 800 m (by up to 2.5 ppm). In an appendix the automated FTS observatory, including the hardware components and the automation software, is described in its basics.

scholarly journals An Idealized Cloud-Resolving Framework for the Study of Midlatitude Diurnal Convection over Land

2011 ◽  
Vol 68 (5) ◽  
pp. 1041-1057 ◽  
Author(s):  
Linda Schlemmer ◽  
Cathy Hohenegger ◽  
Jürg Schmidli ◽  
Christopher S. Bretherton ◽  
Christoph Schär
Keyword(s):  
Boundary Layer ◽  
Relaxation Time ◽  
Planetary Boundary Layer ◽  
Diurnal Cycle ◽  
Lower Troposphere ◽  
Relaxation Method ◽  
Lower Atmosphere ◽  
Soil Conditions ◽  
Humidity Profile ◽  
Atmospheric Profiles

Abstract This paper introduces an idealized cloud-resolving modeling (CRM) framework for the study of midlatitude diurnal convection over land. The framework is used to study the feedbacks among soil, boundary layer, and diurnal convection. It includes a setup with explicit convection and a full set of parameterizations. Predicted variables are constantly relaxed toward prescribed atmospheric profiles and soil conditions. The relaxation is weak in the lower troposphere and upper soil to allow the development of a realistic diurnal planetary boundary layer. The model is run to its own equilibrium (30 days). The framework is able to produce a realistic timing of the diurnal cycle of convection. It also confirms the development of deeper convection in a more unstably stratified atmosphere. With this relaxation method, the simulated “diurnal equilibrium convection” determines the humidity profile of the lower atmosphere, and the simulation becomes insensitive to the reference humidity profile. However, if a faster relaxation time is used in the lower troposphere, the convection and rainfall become much more sensitive to the reference humidity, consistent with previous studies.

scholarly journals Assimilation of Surface-Based Boundary Layer Profiler Observations during a Cool-Season Weather Event Using an Observing System Simulation Experiment. Part I: Analysis Impact

2011 ◽  
Vol 139 (8) ◽  
pp. 2309-2326 ◽  
Author(s):  
Jason A. Otkin ◽  
Daniel C. Hartung ◽  
David D. Turner ◽  
Ralph A. Petersen ◽  
Wayne F. Feltz ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Simulation Experiment ◽  
System Simulation ◽  
Microwave Radiometer ◽  
Lower Troposphere ◽  
Moisture Profile ◽  
Wind Profiles ◽  
Observing System Simulation Experiment ◽  
The Impact

AbstractIn this study, an Observing System Simulation Experiment was used to examine how the assimilation of temperature, water vapor, and wind profiles from a potential array of ground-based remote sensing boundary layer profiling instruments impacts the accuracy of atmospheric analyses when using an ensemble Kalman filter data assimilation system. Remote sensing systems evaluated during this study include the Doppler wind lidar (DWL), Raman lidar (RAM), microwave radiometer (MWR), and the Atmospheric Emitted Radiance Interferometer (AERI). The case study tracked the evolution of several extratropical weather systems that occurred across the contiguous United States during 7–8 January 2008. Overall, the results demonstrate that using networks of high-quality temperature, wind, and moisture profile observations of the lower troposphere has the potential to improve the accuracy of wintertime atmospheric analyses over land. The impact of each profiling system was greatest in the lower and middle troposphere on the variables observed or retrieved by that instrument; however, some minor improvements also occurred in the unobserved variables and in the upper troposphere, particularly when RAM observations were assimilated. The best analysis overall was achieved when DWL wind profiles and temperature and moisture observations from the RAM, AERI, or MWR were assimilated simultaneously, which illustrates that both mass and momentum observations are necessary to improve the analysis accuracy.

scholarly journals Airborne observation of mixing across the entrainment zone during PARADE 2011

2015 ◽  
Vol 15 (20) ◽  
pp. 29171-29212 ◽  
Author(s):  
F. Berkes ◽  
P. Hoor ◽  
H. Bozem ◽  
D. Kunkel ◽  
M. Sprenger ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Dynamic Properties ◽  
Inversion Layer ◽  
Lower Troposphere ◽  
Correlation Method ◽  
Late Summer ◽  
Lower Atmosphere ◽  
Boundary Layer Height ◽  
Entrainment Zone ◽  
The Impact

Abstract. This study presents the analysis of the structure and air mass characteristics of the lower atmosphere during the field campaign PARADE (PArticles and RAdicals: Diel observations of the impact of urban and biogenic Emissions) on Mount Kleiner Feldberg in southwestern Germany during late summer 2011. We analysed measurements of meteorological variables (temperature, moisture, pressure, wind speed and direction) from radio soundings and of chemical tracers (carbon dioxide, ozone) from aircraft measurements. We focus on the thermodynamic and dynamic properties, that control the chemical distribution of atmospheric constituents in the boundary layer. We show that the evolution of tracer profiles of CO2 and O3 indicate mixing across the inversion layer (or entrainment zone). This finding is supported by the analysis of tracer–tracer correlations which are indicative for mixing and the relation of tracer profiles in relation to the evolution of the boundary layer height deduced from radio soundings. The study shows the relevance of entrainment processes for the lower troposphere in general and specifically that the tracer–tracer correlation method can be used to identify mixing and irreversible exchange processes across the inversion layer.

Planning for LOTOS: A New LOwer Troposphere Observing System

2020 ◽  
Author(s):  
Terry Hock ◽  
Tammy Weckwerth ◽  
Steve Oncley ◽  
William Brown ◽  
Vanda Grubišić ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Real Time ◽  
Sensor Network ◽  
Regional Scale ◽  
Lower Troposphere ◽  
Integrated System ◽  
Lower Atmosphere ◽  
Time Data ◽  
Wide Range ◽  
Real Time Data

<p>The National Center for Atmospheric Research Earth Observing Laboratory (EOL) proposes to develop the LOwer Troposphere Observing System (LOTOS), a new integrated sensor network that offers the potential for transformative understanding of the lower atmosphere and its coupling to the Earth's surface. </p><p> </p><p>The LOTOS sensor network is designed to allow simultaneous and coordinated sampling both vertically, through the atmospheric planetary boundary layer, and horizontally, across the surrounding landscape, focusing on the land-atmosphere interface and its coupling with the overlying free troposphere. The core of LOTOS will be a portable integrated network of up to five nodes, each consisting of a profiling suite of instruments surrounded by up to fifteen flux measuring towers. LOTOS will provide an integrated set of measurements needed to address outstanding scientific challenges related to processes within the atmospheric surface layer, boundary layer, and lower troposphere. LOTOS will also enable novel quantification of exchanges of biogeochemical and climate-relevant gases from microscale up to regional scale. </p><p> </p><p>LOTOS’ uniqueness lies in its ability to simultaneously sample both horizontally and vertically as an integrated system, but also in its flexibility to be easily relocated as a portable field-deployable system suitable for addressing a wide range of research needs. LOTOS will provide real-time data quality control, combine measurements from a variety of sensors into integrated data products, and provide real-time data displays. It is envisioned that LOTOS will become part of the deployable NSF Lower Atmosphere Observing Facilities (LAOF) and thus be available to a broad base of NSF users from both observational and modeling communities. LOTOS offers the potential for transformative understanding of the Earth and its atmosphere as a coupled system. This presentation will describe the background, motivation, plan, and timeline for the LOTOS’ proposed development.</p>

scholarly journals Radiative and thermodynamic responses to aerosol extinction profiles during the pre-monsoon month over South Asia

2015 ◽  
Vol 15 (12) ◽  
pp. 16901-16943 ◽  
Author(s):  
Y. Feng ◽  
V. R. Kotamarthi ◽  
R. Coulter ◽  
C. Zhao ◽  
M. Cadeddu
Keyword(s):  
Boundary Layer ◽  
South Asia ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Lower Troposphere ◽  
Longwave Radiation ◽  
Radiative Heating ◽  
Lower Atmosphere ◽  
Radiative Effects ◽  
Aerosol Radiative

Abstract. Aerosol radiative effects and thermodynamic responses over South Asia are examined with a version of the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) for March 2012. Model results of Aerosol Optical Depth (AOD) and extinction profiles are analyzed and compared to satellite retrievals and two ground-based lidars located in the northern India. The WRF-Chem model is found to underestimate the AOD during the simulated pre-monsoon month and about 83 % of the model low-bias is due to aerosol extinctions below ~2 km. Doubling the calculated aerosol extinctions below 850 hPa generates much better agreement with the observed AOD and extinction profiles averaged over South Asia. To separate the effect of absorption and scattering properties, two runs were conducted: in one run (Case I), the calculated scattering and absorption coefficients were increased proportionally, while in the second run (Case II) only the calculated aerosol scattering coefficient was increased. With the same AOD and extinction profiles, the two runs produce significantly different radiative effects over land and oceans. On the regional mean basis, Case I generates 48 % more heating in the atmosphere and 21 % more dimming at the surface than Case II. Case I also produces stronger cooling responses over the land from the longwave radiation adjustment and boundary layer mixing. These rapid adjustments offset the stronger radiative heating in Case I and lead to an overall lower-troposphere cooling up to −0.7 K day−1, which is smaller than that in Case II. Over the ocean, direct radiative effects dominate the heating rate changes in the lower atmosphere lacking such surface and lower atmosphere adjustments due to fixed sea surface temperature, and the strongest atmospheric warming is obtained in Case I. Consequently, atmospheric dynamics (boundary layer heights and meridional circulation) and thermodynamic processes (water vapor and cloudiness) are shown to respond differently between Case I and Case II underlying the importance of determining the exact portion of scattering or absorbing aerosols that lead to the underestimation of aerosol optical depth in the model. In addition, the model results suggest that both direct radiative effect and rapid thermodynamic responses need to be quantified for understanding aerosol radiative impacts.

Impact of Ground-Based Remote Sensing Boundary Layer Observations on Short-Term Probabilistic Forecasts of a Tornadic Supercell Event

2019 ◽  
Vol 34 (5) ◽  
pp. 1453-1476 ◽  
Author(s):  
Junjun Hu ◽  
Nusrat Yussouf ◽  
David D. Turner ◽  
Thomas A. Jones ◽  
Xuguang Wang
Keyword(s):  
Remote Sensing ◽  
Boundary Layer ◽  
Temporal Resolution ◽  
Numerical Models ◽  
Horizontal Wind ◽  
High Temporal Resolution ◽  
Short Term ◽  
Probabilistic Forecasts ◽  
Convective Scale ◽  
The Impact

Abstract Due to lack of high spatial and temporal resolution boundary layer (BL) observations, the rapid changes in the near-storm environment are not well represented in current convective-scale numerical models. Better representation of the near-storm environment in model initial conditions will likely further improve the forecasts of severe convective weather. This study investigates the impact of assimilating high temporal resolution BL retrievals from two ground-based remote sensing instruments for short-term forecasts of a tornadic supercell event on 13 July 2015 during the Plains Elevated Convection At Night field campaign. The instruments are the Atmospheric Emitted Radiance Interferometer (AERI) that retrieves thermodynamic profiles and the Doppler lidar (DL) that measures horizontal wind profiles. Six sets of convective-scale ensemble data assimilation (DA) experiments are performed: two control experiments that assimilate conventional and WSR-88D radar observations using either relaxation-to-prior-spread (RTPS) or the adaptive inflation (AI) technique and four experiments similar to the control but that assimilate either DL or AERI or both observations in addition to all other observations that are in the control experiments. Results indicate a positive impact of AERI and DL observations in forecasting convective initiation (CI) and early evolution of the supercell storm. The experiment that employs the AI technique to assimilate BL observations in DA enhances the humidity in the near-storm environment and low-level convergence, which in turn helps forecasting CI. The forecast improvement is most pronounced during the first ~3 h. Results also indicate that the AERI observations have a larger impact compared to DL in predicting CI.

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