Spectral measurement of watershed coefficients in the southern Great Plains
There are no author-identified significant results in this report.
Blanchard, B. J.↗
Engineering topics
Blanchard, B. J.
Publications and source records attributed to Blanchard, B. J..
Analysis of synthetic aperture radar imagery
The author has identified the following significant results. Average radar response for L-band like polarized system appeared to be related to the watershed runoff coefficients when the viewing angle was approximately 42 deg off nadir. Four requirements for radar systems used to verify applications of active microwave for water resources were identified: (1) first generation digital data will be required; (2) radar should be calibrated both internally and externally; (3) new systems should avoid radom use; and (4) images should be geometrically rectified prior to delivery to the user.
Blanchard, B. J.↗
Spectral measurement of watershed coefficients in the southern Great Plains
There are no author-identified significant results in this report.
Blanchard, B. J.↗
Spectral measurement of watershed coefficients in the southern Great Plains
There are no author-identified significant results in this report.
Blanchard, B. J.↗
Results of soil moisture flights during April 1974
The results presented here are derived from measurements made during the April 5 and 6, 1974 flights of the NASA P-3A aircraft over the Phoenix, Arizona agricultural test site. The purpose of the mission was to study the use of microwave techniques for the remote sensing of soil moisture. These results include infrared (10-to 12 micrometers) 2.8-cm and 21-cm brightness temperatures for approximately 90 bare fields. These brightness temperatures are compared with surface measurements of the soil moisture made at the time of the overflights. These data indicate that the combination of the sum and difference of the vertically and the horizontally polarized brightness temperatures yield information on both the soil moisture and surface roughness conditions.
Schmugge, T. J.↗
Spectral measurement of watershed coefficients in the southern Great Plains
There are no author-identified significant results in this report.
Blanchard, B. J.↗
Spectral measurement of watershed coefficients in the southern Great Plains
There are no author-identified significant results in this report.
Blanchard, B. J.↗
Ground truth report 1975 Phoenix microwave experiment
Direct measurements of soil moisture obtained in conjunction with aircraft data flights near Phoenix, Arizona in March, 1975 are summarized. The data were collected for the Joint Soil Moisture Experiment.
Blanchard, B. J.↗
Remote sensing techniques for prediction of watershed runoff
Hydrologic parameters of watersheds for use in mathematical models and as design criteria for flood detention structures are sometimes difficult to quantify using conventional measuring systems. The advent of remote sensing devices developed in the past decade offers the possibility that watershed characteristics such as vegetative cover, soils, soil moisture, etc., may be quantified rapidly and economically. Experiments with visible and near infrared data from the LANDSAT-1 multispectral scanner indicate a simple technique for calibration of runoff equation coefficients is feasible. The technique was tested on 10 watersheds in the Chickasha area and test results show more accurate runoff coefficients were obtained than with conventional methods. The technique worked equally as well using a dry fall scene. The runoff equation coefficients were then predicted for 22 subwatersheds with flood detention structures. Predicted values were again more accurate than coefficients produced by conventional methods.
Blanchard, B. J.↗
Investigation of use of space data in watershed hydrology
The author has identified the following significant results. Digital data from the ERTS multispectral scanner were used to investigate the feasibility of identifying differences in watershed runoff capability with spaceborne sensors. Linear combinations of the two visible light bands and a combination of the four visible and near infrared bands were related to a coefficient used in the Soil Conservation Service storm runoff equation. Good relationships were found in two scenes, both with dry surface conditions, over the same watersheds. The relationships defined by both combinations of digital data were tested on a independent set of 10 watersheds and on an additional 22 subwatersheds. Coefficients predicted with the ERTS data proved better than coefficients developed with conventional methods.
Blanchard, B. J.↗
Measuring watershed runoff capability with ERTS data
Parameters of most equations used to predict runoff from an ungaged area are based on characteristics of the watershed and subject to the biases of a hydrologist. Digital multispectral scanner, MSS, data from ERTS was reduced with the aid of computer programs and a Dicomed display. Multivariate analyses of the MSS data indicate that discrimination between watersheds with different runoff capabilities is possible using ERTS data. Differences between two visible bands of MSS data can be used to more accurately evaluate the parameters than present subjective methods, thus reducing construction cost due to overdesign of flood detention structures.
Blanchard, B. J.↗
Measurements from aircraft to characterize watersheds
Remote sensor measurements of the Southern Plains watershed, an 1130 sq mile segment of the Washita River basin in the Texas Panhandle, are discussed. Soil moisture measurements are emphasized, along with rainfall storage capacity of the soil. Indicators of pond water quality, geologic sources of sediment or salt, and rapid methods of mapping seepage are being searched for through remote sensing.
Blanchard, B. J.↗