Satellite remote sensing of primary production

Leaf structure and function are shown to result in distinctive variations in the absorption and reflection of solar radiation from plant canopies. The leaf properties that determine the radiation-interception characteristics of plant canopies are directly linked to photosynthesis, stomatal resistance and evapotran-spiration and can be inferred from measurements of reflected solar energy. The effects of off-nadir viewing and atmospheric constituents, coupled with the need to measure changing surface conditions, emphasize the need for multitemporal measurements of reflected radiation if primary production is to be estimated     

Monitoring the grasslands of the Sahel 1984-1985

Normalized difference vegetation index data obtained from polar-orbiting meteorological satellites were used to compare the growing or rainy seasons of 1984 and 1985 for the Sahelian zone of Africa. A substantial difference was found between these two years, with 1985 generally having higher normalized difference vegetation index values indicating higher levels of primary production in 1985 than in 1984. 1 km data were compared for Senegal, Mali, Niger and Sudan, and 7 km data were compared for sub-Saharan Africa. The qualitative comparison of these data suggests the use of similar data to assist in centralized monitoring of rangeland conditions, to identify areas of deficiencies in primary production and provide synoptic information in support of regional drought monitoring     

A comparison of SMMR and AVHRR data for continental land cover characterization

Abstract

Images using reflected visible and near-infrared data and images using passive microwave data were compared in terms of their usefulness for characterizing land-cover types in South America and Africa. The former images are of the normalized difference vegetation index (NDVI) subsampled to approximately 15-20 km resolution in the NOAA global vegetation index product. The latter images of the microwave polarization difference temperature (MPDT) are derived from the difference between horizontally and vertically polarized radiation in the 37 GHz band. Results of maximum-likelihood classifications applied to multi-temporal data sets indicate that, overall, the NDVI data sets are substantially better than the MPDT data sets for land-cover characterization. However, the greater sensitivity of the MPDT data in semi-arid areas results in their superior performance for some classes in these areas. The combined use of MPDT and NDVI data sets show clear synergistic benefits in using the two data sets. However, the evidence suggests that for most cover types, increasing the temporal frequency of the NDVI images is more advantageous than incorporating MPDT data sets.     

PREDICTION OF CREATIVITY AND OTHER PERFORMANCE MEASURES FROM BIOGRAPHICAL INFORMATION AMONG PHARMACEUTICAL SCIENTISTS.

A 160-ITEM BIOGRAPHICAL INVENTORY WAS ADMINISTERED TO 157 PHARMACEUTICAL SCIENTISTS WHO WERE RANDOMLY ASSIGNED TO 2 GROUPS OF 79 AND 78 SS. EACH ALTERNATIVE FROM EACH ITEM IN THE INVENTORY WAS CORRELATED WITH 19 CRITERION MEASURES OBTAINED ON EACH OF THE SCIENTISTS. THESE PRIMARILY INVOLVED RATINGS OF CREATIVITY, QUANTITY OF WORK PRODUCED, SKILL WITH PEOPLE, ETC., OBTAINED FROM SUPERVISORS, PEERS, AND SUBORDINATES. REMARKABLY LITTLE RELATIONSHIP EXISTED BETWEEN SUPERVISORY AND PEER RATINGS OF THE SCIENTISTS ON MOST VARIABLES. USING A DOUBLE CROSS-VALIDATION DESIGN, INVENTORY PREDICTOR KEYS WERE DEVELOPED FOR EACH OF THE CRITERION RATINGS AND APPLIED ACROSS TO THE NEW INDEPENDENT SAMPLE. SIGNIFICANT CROSS VALIDITIES WERE OBTAINED, NOTABLY IN THE PREDICTION OF THE CREATIVITY CRITERION, WHERE CORRELATIONS OF .36 AND .42 RESULTED ACROSS THE 2 SUBSAMPLES. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

DETERMINATION of RESIDENCE TIME DISTRIBUTION of NONSETTLING FOOD PARTICLES IN VISCOUS FOOD CARRIER FLUIDS USING HALL EFFECT SENSORS

Hall effect sensors were used to determine residence time distributions for diced carrot particles in 4% Colflo 67 carrier fluid. Four sensors at either end of a 3.2 m long 2 in. IDF tube viscometer allowed residence times to be measured for carrot particles incorporating a ceramic magnet. Mean particle residence times were greater than mean bulk residence time for 8 mm diced carrots, whereas 15 mm carrots showed trials in which particles travelled faster than the bulk fluid. Increasing concentration of 15 mm diced carrots from 3.25, 6.30, 9.16 to 11.85% w/w resulted in decreasing mean particle residence times from 17.6, 17.0, 15.9 to 14.3 s, with minimum residence times of 16.4, 16.2, 14.8 and 13.4 s, respectively. This sensing technique operates through stainless steel, providing applications for UHT foods containing particles. In addition, the technique was not affected by high particle concentration, and will operate for any distribution of particle size, shape or type.     

Modelling the cooling phase of heat sterilization processes, using heat transfer coefficients

A mathematical model based on finite differences was presented, which improved the accuracy of current modelling techniques during the cooling period for conduction heating foods undergoing thermal processing. The surface heat transfer coefficient between can and cooling fluid was incorporated into the finite difference equations, with a value of 600 W m⁻² K⁻¹ chosen from literature and confirmed by calculations from surface temperature measurements and a correlation of the form Nu = f(GrxPr)ⁿ.
Experimental results were obtained for a cylinder of Sylgard 184 elastomer (length 62mm, diameter 57mm) and a polypropylene block (26x91x141 mm). At the end of cooling the heat transfer coefficient model predicted a centre temperature just 2.5°C above the measured value for polypropylene, and for Sylgard 184 this difference was 2.7°C.
This model will improve both real-time process control via the 'derived-value' technique, and the use of controlled pressure cooling with less damage to containers. Optimization of quality factors will also be improved with increased knowledge of in-container temperatures.     

Determination of volcanic dust deposition from El Chichon using ground and satellite data

Major volcanic eruptions of EI Chichon on 28 March 1982, 3 April 1982 and 4 April 1982 produced heavy tephra falls in surrounding areas. Data from the NOAA-6 and NOAA-7 satellites were used to determine the extent of the tephra falls. The satellite data showed a larger area of tephra deposition than was reported from conventional ground measurements     

Fraction images derived from NOAA AVHRR data for studying the deforestation in the Brazilian Amazon

Considerable variation in the performance of passive microwave global rainfall algorithms, both spatially and temporally,was revealed by the first WetNet Precipitation Intercomparison Project, PIP-1, with no one algorithm achieving the best results, in all locations, and all the time. In this paper a Composite Algorithm Procedure is described for the Special Sensor Microwave/Imager (SSM/I) algorithms submitted to PIP-1, that attempts through combining the best algorithm results from different regions of the globe to achieve better overall global rainfall estimates than are possible from any individual algorithm alone. The Composite Algorithm Procedure (CAP) involves the segmentation of the globe into homogeneous regions, the production of validation statistics for the various algorithm results in the different regions, and the identification of combinations of algorithms which perform best globally. The segmentations were based on aspects of the spatial and temporal variability of rainfall, or the microwave properties of the surfaces of the Earth. Initial results for the Composite Algorithm Procedure are presented for a sample month (October 1987): these confirm that improved global rainfall products can be produced in this way. Code detailing a selected Composite Algorithm based on the segmentation method of the microwave properties of the Earth has been supplied to the WetNet Support Group at the Marshall Space Flight Center, Huntsville, Alabama, for experimental, regular production of global rainfall data sets on a near real-time basis.     

Comment on the article “Estimation of sugar beet productivity from reflection in the red and infrared spectral bands”

Abstract

An allegation that has been made that we have placed excessive weight on measurements of spectral ratios for winter wheat early in the season is refuted.