Lidar observations of a mesoscale moisture transport event impacting convection and comparison to Rapid Refresh model analysis

2020 ◽  
Author(s):  
Brian J. Carroll ◽  
Belay B. Demoz ◽  
David D. Turner ◽  
Ruben Delgado
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Great Plains ◽  
Large Scale ◽  
Spatial Scales ◽  
Airborne Lidar ◽  
Water Vapor Transport ◽  
Analysis Model ◽  
Vapor Flux ◽  
Lidar Observations

AbstractThe 2015 Plains Elevated Convection at Night (PECAN) field campaign provided a wealth of intensive observations for improving understanding of interplay between the Great Plains low-level jet (LLJ), mesoscale convective systems (MCSs), and other phenomena in the nocturnal boundary layer. This case study utilizes PECAN ground-based Doppler and water vapor lidar and airborne water vapor lidar observations for a detailed examination of water vapor transport in the Great Plains. The chosen case, 11 July 2015, featured a strong LLJ that helped sustain an MCS overnight. The lidars resolved boundary layer moisture being transported northward, leading to a large increase in water vapor in the lowest several hundred meters above the surface in northern Kansas. A branch of nocturnal convection initiated coincident with the observed maximum water vapor flux. Radiosondes confirmed an increase in convective potential within the LLJ layer. Moist static energy (MSE) growth was generated by increasing moisture in spite of a temperature decrease in the LLJ layer. This unique dataset is also used to evaluate the Rapid Refresh (RAP) analysis model performance, comparing model output against the continuous lidar profiles of water vapor and wind. While the RAP analysis captured the large-scale trends, errors in water vapor mixing ratio were found ranging 0 to 2 g/kg at the ground-based lidar sites. Comparison with the airborne lidar throughout the PECAN domain yielded a RMSE of 1.14 g/kg in the planetary boundary layer. These errors mostly manifested as contiguous dry or wet regions spanning spatial scales of O(10s-100s km).

scholarly journals Lidar Observations Versus Forecast of Water Vapor Transport

2020 ◽  
Vol 237 ◽  
pp. 06008
Author(s):  
Brian Carroll ◽  
Belay Demoz ◽  
Ruben Delgado
Keyword(s):  
Water Vapor ◽  
Great Plains ◽  
Temporal Evolution ◽  
Forecast Model ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Forecast System ◽  
Convective Systems ◽  
The North ◽  
Lidar Observations

Water vapor advection is an important diagnostic parameter for initiation and sustenance of convective systems. This variable has traditionally been explored with balloon soundings or models, but lidar provides a unique opportunity to continuously resolve spatial and temporal evolution of water vapor transport with relatively high resolution. In this study we utilize co-located Doppler wind lidars and water vapor lidars (DIAL and Raman) at multiple sites to investigate water vapor advection. A case of nocturnal convection in the Great Plains is analyzed with these observations and compared to the North American Mesoscale Forecast System (NAM) operational forecast model.

scholarly journals Observations of water vapor mixing ratio profile and flux in the Tibetan Plateau based on the lidar technique

2016 ◽  
Vol 9 (3) ◽  
pp. 1399-1413 ◽  
Author(s):  
Songhua Wu ◽  
Guangyao Dai ◽  
Xiaoquan Song ◽  
Bingyi Liu ◽  
Liping Liu
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Tibetan Plateau ◽  
Large Scale ◽  
Lower Troposphere ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Mixing Ratio ◽  
Wind Lidar ◽  
Water Vapor Mixing Ratio

Abstract. As a part of the third Tibetan Plateau Experiment of Atmospheric Sciences (TIPEX III) in China, a Raman water vapor, cloud and aerosol lidar and a coherent wind lidar were operated in Naqu (31.48° N, 92.06° E) with a mean elevation of more than 4500 m a.m.s.l. in summer of 2014. During the field campaign, the water vapor mixing ratio profiles were obtained and validated by radiosonde observations. The mean water vapor mixing ratio in Naqu in July and August was about 9.4 g kg−1 and the values vary from 6.0 to 11.7 g kg−1 near the ground according to the lidar measurements, from which a diurnal variation of water vapor mixing ratio in the planetary boundary layer was also illustrated in this high-elevation area. Furthermore, using concurrent measurements of vertical wind speed profiles from the coherent wind lidar, we calculated the vertical flux of water vapor that indicates the water vapor transport through updraft and downdraft. The fluxes were for a case at night with large-scale non-turbulent upward transport of moisture. It is the first application, to our knowledge, to operate continuously atmospheric observations by utilizing multi-disciplinary lidars at the altitude higher than 4000 m, which is significant for research on the hydrologic cycle in the atmospheric boundary layer and lower troposphere in the Tibetan Plateau.

scholarly journals Airborne lidar observations of water vapor transport

2012 ◽  
Author(s):  
Christoph Kiemle ◽  
Andreas Schafler ◽  
Martin Wirth ◽  
Andreas Fix ◽  
Stephan Rahm
Keyword(s):  
Water Vapor ◽  
Airborne Lidar ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Lidar Observations

scholarly journals Extreme Floods in the Eastern Part of Europe: Large-Scale Drivers and Associated Impacts

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1122
Author(s):  
Monica Ionita ◽  
Viorica Nagavciuc
Keyword(s):  
Water Vapor ◽  
Heavy Rainfall ◽  
Large Scale ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Flood Events ◽  
Rainfall Events ◽  
Catchment Areas ◽  
Large Scale Atmospheric Circulation ◽  
Heavy Rainfall Events

The role of the large-scale atmospheric circulation in producing heavy rainfall events and floods in the eastern part of Europe, with a special focus on the Siret and Prut catchment areas (Romania), is analyzed in this study. Moreover, a detailed analysis of the socio-economic impacts of the most extreme flood events (e.g., July 2008, June–July 2010, and June 2020) is given. Analysis of the largest flood events indicates that the flood peaks have been preceded up to 6 days in advance by intrusions of high Potential Vorticity (PV) anomalies toward the southeastern part of Europe, persistent cut-off lows over the analyzed region, and increased water vapor transport over the catchment areas of Siret and Prut Rivers. The vertically integrated water vapor transport prior to the flood peak exceeds 300 kg m−1 s−1, leading to heavy rainfall events. We also show that the implementation of the Flood Management Plan in Romania had positive results during the 2020 flood event compared with the other flood events, when the authorities took several precaution measurements that mitigated in a better way the socio-economic impact and risks of the flood event. The results presented in this study offer new insights regarding the importance of large-scale atmospheric circulation and water vapor transport as drivers of extreme flooding in the eastern part of Europe and could lead to a better flood forecast and flood risk management.

scholarly journals Coupling between Large-Scale Atmospheric Processes and Mesoscale Land–Atmosphere Interactions in the U.S. Southern Great Plains during Summer. Part II: Mean Impacts of the Mesoscale

2004 ◽  
Vol 5 (6) ◽  
pp. 1247-1258 ◽  
Author(s):  
Christopher P. Weaver
Keyword(s):  
Case Studies ◽  
Time Scales ◽  
Great Plains ◽  
Large Scale ◽  
Spatial Scales ◽  
Surface Heterogeneity ◽  
Atmospheric Modeling ◽  
Mesoscale Circulations ◽  
Southern Great Plains ◽  
Atmospheric Processes

Abstract This is Part II of a two-part study of mesoscale land–atmosphere interactions in the summertime U.S. Southern Great Plains. Part I focused on case studies drawn from monthlong (July 1995–97), high-resolution Regional Atmospheric Modeling System (RAMS) simulations carried out to investigate these interactions. These case studies were chosen to highlight key features of the lower-tropospheric mesoscale circulations that frequently arise in this region and season due to mesoscale heterogeneity in the surface fluxes. In this paper, Part II, the RAMS-simulated mesoscale dynamical processes described in the Part I case studies are examined from a domain-averaged perspective to assess their importance in the overall regional hydrometeorology. The spatial statistics of key simulated mesoscale variables—for example, vertical velocity and the vertical flux of water vapor—are quantified here. Composite averages of the mesoscale and large-scale-mean variables over different meteorological or dynamical regimes are also calculated. The main finding is that, during dry periods, or similarly, during periods characterized by large-scale-mean subsidence, the characteristic signature of surface-heterogeneity-forced mesoscale circulations, including enhanced vertical motion variability and enhanced mesoscale fluxes in the lowest few kilometers of the atmosphere, consistently emerges. Furthermore, the impact of these mesoscale circulations is nonnegligible compared to the large-scale dynamics at domain-averaged (200 km × 200 km) spatial scales and weekly to monthly time scales. These findings support the hypothesis that the land– atmosphere interactions associated with mesoscale surface heterogeneity can provide pathways whereby diurnal, mesoscale atmospheric processes can scale up to have more general impacts at larger spatial scales and over longer time scales.

scholarly journals Convective boundary layer evolution to 4 km asl over High-alpine terrain: Airborne lidar observations in the Alps

2000 ◽  
Vol 27 (5) ◽  
pp. 689-692 ◽  
Author(s):  
S. Nyeki ◽  
M. Kalberer ◽  
I. Colbeck ◽  
S. De Wekker ◽  
M. Furger ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Convective Boundary Layer ◽  
Airborne Lidar ◽  
Convective Boundary ◽  
The Alps ◽  
Lidar Observations

Estimation of the precipitable water and water vapor flux using MAX-DOAS in two typical  cities of China

2021 ◽  
Author(s):  
Hongmei Ren ◽  
Ang Li ◽  
Pinhua Xie ◽  
Zhaokun Hu ◽  
Jin Xu ◽  
...  
Keyword(s):  
Water Vapor ◽  
Precipitable Water ◽  
Reanalysis Data ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Optical Absorption Spectroscopy ◽  
Water Vapor Flux ◽  
Vapor Flux ◽  
The North ◽  
Two Cities

<p>      Water vapor transport affects regional precipitation and climate change. The measurement of precipitable water and water vapor flux is of great significance to the study of precipitation and water vapor transport. In the study, a new method of computing the precipitable water and estimating the water vapor transport flux using multi-axis differential optical absorption spectroscopy (MAX-DOAS) were presented. The calculated precipitable water and water vapor flux were compared to the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data and the correlation coefficient of the precipitable water, the zonal and meridional water vapor flux and ECMWF are r≥0.92, r=0.77 and r≥0.89, respectively. The seasonal and diurnal climatologies of precipitable water and water vapor flux in the coastal (Qingdao) and inland (Xi’an) cities of China using this method were analyzed from June 1, 2019 to May 31, 2020. The results indicated that the seasonal and diurnal variation characteristics of the precipitable water in the two cities were similar. The zonal fluxes of the two cities were mainly transported from west to east, Qingdao's meridional flux was mainly transported to the south, and Xi'an was mainly transported to the north. The results also indicated that the water vapor flux transmitting belts appear near 2km and 1.4km above the surface in Qingdao and appeared around 2.8km, 1.6km and 1.0km in Xi'an. </p>

Response of Seasonal Simulations of a Regional Climate Model to High-Frequency Variability of Soil Moisture during the Summers of 1988 and 1993

2007 ◽  
Vol 8 (4) ◽  
pp. 738-757 ◽  
Author(s):  
Song Yang ◽  
S-H. Yoo ◽  
R. Yang ◽  
K. E. Mitchell ◽  
H. van den Dool ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Vapor ◽  
Diurnal Cycle ◽  
High Frequency ◽  
Large Scale ◽  
Climate Model ◽  
Regional Climate ◽  
Water Vapor Transport ◽  
Diurnal Variability ◽  
High Frequency Variability

Abstract This study employs the NCEP Eta Regional Climate Model to investigate the response of the model’s seasonal simulations of summer precipitation to high-frequency variability of soil moisture. Specifically, it focuses on the response of model precipitation and temperature over the U.S. Midwest and Southeast to imposed changes in the diurnal and synoptic variability of soil moisture in 1988 and 1993. High-frequency variability of soil moisture increases (decreases) precipitation in the 1988 drought (1993 flood) year in the central and southern-tier states, except along the Gulf Coast, but causes smaller changes in precipitation along the northern-tier states. The diurnal variability and synoptic variability of soil moisture produce similar patterns of precipitation change, indicating the importance of the diurnal cycle of land surface process. The increase (decrease) in precipitation is generally accompanied by a decrease (increase) in surface and lower-tropospheric temperatures, and the changes in precipitation and temperature are attributed to both the local effect of evaporation feedback and the remote influence of large-scale water vapor transport. The precipitation increase and temperature decrease in 1988 are accompanied by an increase in local evaporation and, more importantly, by an increase in the large-scale water vapor convergence into the Midwest and Southeast. Analogous but opposite-sign behavior occurs in 1993 (compared to 1988) in changes in precipitation, temperature, soil moisture, evaporation, and large-scale water vapor transport. Results also indicate that, in regions where the model simulates the diurnal cycle of soil moisture reasonably well, including this diurnal cycle in the simulations improves model performance. However, no notable improvement in model precipitation can be found in regions where the model fails to realistically simulate the diurnal variability of soil moisture.

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