scholarly journals Near-surface moisture and biomass influences on the reliability of aerial radiometric surveys as a measure of natural radioelement concentrations

1979 ◽  
Author(s):  
J.R. Norwine ◽  
D.J. Hansen ◽  
D.F. Saunders ◽  
J.H. Galbraith
Keyword(s):  
Near Surface ◽  
Surface Moisture ◽  
Natural Radioelement

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

1998 ◽  
Vol 37 (3) ◽  
pp. 308-324 ◽  
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.

scholarly journals Convective environment in pre-monsoon and monsoon conditions over the Indian subcontinent: the impact of surface forcing

2018 ◽  
Vol 18 (10) ◽  
pp. 7473-7488 ◽  
Author(s):  
Lois Thomas ◽  
Neelam Malap ◽  
Wojciech W. Grabowski ◽  
Kundan Dani ◽  
Thara V. Prabha
Keyword(s):  
Indian Subcontinent ◽  
High Surface ◽  
Convective Available Potential Energy ◽  
Bowen Ratio ◽  
Heat Fluxes ◽  
Tropospheric Temperature ◽  
Theoretical Argument ◽  
Near Surface ◽  
Surface Moisture ◽  
The Impact

Abstract. Thermodynamic soundings for pre-monsoon and monsoon seasons from the Indian subcontinent are analysed to document differences between convective environments. The pre-monsoon environment features more variability for both near-surface moisture and free-tropospheric temperature and moisture profiles. As a result, the level of neutral buoyancy (LNB) and pseudo-adiabatic convective available potential energy (CAPE) vary more for the pre-monsoon environment. Pre-monsoon soundings also feature higher lifting condensation levels (LCLs). LCL heights are shown to depend on the availability of surface moisture, with low LCLs corresponding to high surface humidity, arguably because of the availability of soil moisture. A simple theoretical argument is developed and showed to mimic the observed relationship between LCLs and surface moisture. We argue that the key element is the partitioning of surface energy flux into its sensible and latent components, that is, the surface Bowen ratio, and the way the Bowen ratio affects surface buoyancy flux. We support our argument with observations of changes in the Bowen ratio and LCL height around the monsoon onset, and with idealized simulations of cloud fields driven by surface heat fluxes with different Bowen ratios.

scholarly journals Two-dimensional variational analysis of near-surface moisture from simulated radar refractivity-related phase change observations

2013 ◽  
Vol 30 (2) ◽  
pp. 291-305 ◽  
Author(s):  
Ken-ichi Shimose ◽  
Ming Xue ◽  
Robert D. Palmer ◽  
Jidong Gao ◽  
Boon Leng Cheong ◽  
...  
Keyword(s):  
Phase Change ◽  
Variational Analysis ◽  
Two Dimensional ◽  
Near Surface ◽  
Surface Moisture ◽  
Related Phase

scholarly journals Effects of soil‐moisture content on shallow‐seismic data

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1357-1362 ◽  
Author(s):  
Robert D. Jefferson ◽  
Don W. Steeples ◽  
Ross A. Black ◽  
Tim Carr
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Seismic Data ◽  
Soil Moisture Content ◽  
Soil Conditions ◽  
Near Surface ◽  
Surface Moisture ◽  
Shallow Seismic ◽  
Unconsolidated Material ◽  
Moisture Conditions

Repeated shallow‐seismic experiments were conducted at a site on days with different near‐surface moisture conditions in unconsolidated material. Experimental field parameters remained constant to ensure comparability of results. Variations in the seismic data are attributed to the changes in soil‐moisture content of the unconsolidated material. Higher amplitudes of reflections and refractions were obtained under wetter near‐surface conditions. An increase in amplitude of 21 dB in the 100–300 Hz frequency range was observed when the moisture content increased from 18% to 36% in the upper 0.15 m (0.5 ft) of the subsurface. In the time‐domain records, highly saturated soil conditions caused large‐amplitude ringy wavelets that interfered with and degraded the appearance of some of the reflection information in the raw field data. This may indicate that an intermediate near‐surface moisture content is most conducive to the recording of high‐quality shallow‐seismic reflection data at this site. This study illustrates the drastic changes that can occur in shallow‐seismic data due to variations in near‐surface moisture conditions. These conditions may need to be considered to optimize the acquisition timing and parameters prior to collection of data.

A new method for measuring near-surface moisture budgets in hydrological systems

1994 ◽  
Vol 154 (1-4) ◽  
pp. 245-254 ◽  
Author(s):  
W.E. Bardsley ◽  
D.I. Campbell
Keyword(s):  
New Method ◽  
Near Surface ◽  
Surface Moisture

How Near-Surface Moisture Gradients Affect Phosphorous and Nitrate Losses

2013 ◽  
Author(s):  
Fenli Zheng ◽  
Chi-hua Huang ◽  
L. Darrell Norton
Keyword(s):  
Near Surface ◽  
Surface Moisture ◽  
Nitrate Losses

scholarly journals Simulation and Interpretation of the Phase Data Used by the Radar Refractivity Retrieval Algorithm

2010 ◽  
Vol 27 (8) ◽  
pp. 1286-1301 ◽  
Author(s):  
Shinju Park ◽  
Frédéric Fabry
Keyword(s):  
Phase Measurement ◽  
Vertical Gradient ◽  
Retrieval Algorithm ◽  
Near Surface ◽  
Phase Measurements ◽  
Surface Moisture ◽  
Atmospheric Propagation ◽  
Phase Fields ◽  
Ray Path

Abstract The radar refractivity retrieval algorithm applied to radar phase measurements from ground targets can provide high-resolution, near-surface moisture estimates in time and space. The reliability of the retrieval depends on the quality of the returned phase measurements, which are affected by factors such as 1) the vertical variation of the refractive index along the ray path and 2) the properties of illuminated ground targets (e.g., the height and shape of the targets intercepted by radar rays over complex terrain). These factors introduce ambiguities in the phase measurement that have not yet been considered in the refractivity algorithm and that hamper its performance. A phase measurement simulator was designed to better understand the effect of these factors. The results from the simulation were compared with observed phase measurements for selected atmospheric propagation conditions estimated from low-level radio sounding profiles. Changes in the vertical gradient of refractivity coupled with the varying heights of targets are shown to have some influence on the variability of phase fields. However, they do not fully explain the noisiness of the real phase observations because other factors that are not included in the simulation, such as moving ground targets, affect the noisiness of phase measurements.

Spectral detection of near-surface moisture content and water-table position in northern peatland ecosystems

2014 ◽  
Vol 152 ◽  
pp. 536-546 ◽  
Author(s):  
Karl M. Meingast ◽  
Michael J. Falkowski ◽  
Evan S. Kane ◽  
Lynette R. Potvin ◽  
Brian W. Benscoter ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Table ◽  
Near Surface ◽  
Surface Moisture ◽  
Spectral Detection
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