Satellite remote sensing of primary production: comparison of results for Sahelian grasslands 1981-1988

Abstract

Field measurements of primary production in semi-arid grasslands in three Sahelian countries over a period of 8 years are analysed in conjunction with multitemporal sums of vegetation indices derived from the NOAA spacecraft's advanced very high resolution radiometer (AVHRR). The results demonstrate that there is a strong linear relationship between the satellite observations of vegetation indices and the seasonal primary production in the range 0-3000?kg ha^?. The confidence intervals of estimation of production were in the range ±61-161 kg ha^?.     

Computer-assisted psychological assessment in 1986: A practical guide

The controversy surrounding computer-assisted psychological assessment is noted, the literature to date surveyed, and suggestions offered for potential consumers. The sparse data currently available indicate that, absent obvious differences in response method, computer and conventional administration of objective personality inventories and ability tests are likely to produce equivalent results. Individuals are sometimes more honest when responding to a computer than when talking to an interviewer. Most people prefer the computer to conventional test administration or interviewing. Data on computer-based test interpretation are few and conflicting. The computer is not yet capable of besting an expert neuropsychologist or, in some cases, physician, but can be programmed to interpret the Minnesota Multiphasic Personality Inventory at least as well as human experts. It is suggested that CBTIs be used as adjuncts in the assessment process rather than as substitutes for informed professional judgement.     

Satellite and ground-based microclimate and hydrologic analyses coupled with a regional urban growth model

Urban development is shown to induce predictable changes in satellite-based measures of radiant surface temperature and evapotranspiration fraction—as long as certain features of the development are known. Specifically, the vegetation changes that accompany the development and the initial climatic state of the land parcel must be noted. Techniques are also developed for quantifying the effects of urbanization on the surface hydrology at a watershed scale. Streamflow and precipitation data are related graphically in order to determine a watershed's general ratio of stormwater runoff to rainfall, along with any changes in the ratio over time. Four distinct runoff responses, separated by season and antecedent moisture conditions, are distinguishable for a particular basin, with the response during the non-summer months under typical antecedent moisture conditions the most representative of and responsive to land-use patterns. This particular runoff response can be estimated from satellite-derived land cover patterns and certain physical attributes of a basin. These satellite-based microclimate and hydrologic analyses are coupled with an existing urban growth model (SLEUTH). The SLEUTH urban growth model simulates future development scenarios for a region of interest. The resulting changes in urban land use lead to the evolution of site-specific climate and hydrology based on the scheme that is presented in this paper. This study, as well as related tools and bodies of knowledge, can be used to broaden the scientific basis behind land-use management decisions.     

Remote sensing capabilities to estimate pasture production in France

Pastures constitute an important terrestrial ecosystem. In France, pastures occupy 21% of the total area. A big effort is being made to develop a real-time systematic approach to estimate biomass production at a national level, focusing on spatial and seasonal variability in relation to drought. The absence of indirect low-cost methods that could be applied to large areas contributes to this situation. Advances in remote sensing and crop models offer new methodological and operative possibilities to solve this problem. In this paper, 13 forage regions (FR) in France were selected on the basis of their different geomorphologic, climatic and soil conditions with regard to pastoral production. Images from Système Probatoire de l'Observation de la Terre (SPOT) 4-VEGETATION were used to forecast productive variables estimated by the STICS-Prairie simulation model. In general terms, both satellite and productive data agreed properly. Particularly, the relationship between the middle infrared based vegetation index (SWVI) and the Leaf Area Index (LAI) demonstrated the best results whatever the FR. Results obtained confirm the capabilities of remote sensing data as an accurate predictor of productive variables estimated as from simulation models. Differences between satellite information and model estimations of pasture systems, especially during the harvesting periods, could be good indicators to improve model estimations at a regional scale as well.     

Satellite and ground-based monitoring of smoke in the atmosphere during the summer wildfires in European Russia in 2010 and Siberia in 2012

Using Moderate Resolution Imaging Spectroradiometer (MODIS) (Aqua and Terra satellites) and in situ observations, a comparative analysis of two large-scale smoke events caused by the summer wildfires in European Russia (ER) in 2010 and Western Siberia (WS) in 2012 was carried out. In the 5-day periods of the extreme smoke pollution (5–9 August 2010 in ER and 27–31 July 2012 in WS), the number of active fires in the equal territories, confined by the coordinates 47°–65° N, 25°–55° E and 51°–70° N, 71°–104° E, was found to be 4754 for ER and 3823 for WS. With this, the regional mean aerosol optical depths (AODs) were found to be (1.02 ± 0.02) and (1.00 ± 0.04), not much differing for both the events. The regional mean aerosol radiative forcing effects at the top (R₁) and the bottom (R₂) of the atmosphere over ER/WS according to MODIS observations were estimated to be (?61 ± 1) and (?54 ± 2) W m^?2, and (?107 ± 2) and (?96 ± 3) W m^?2, respectively. At the same time, the local values of AOD and the local absolute values of R₁ and R₂ over WS were considerably higher than those over ER. MODIS AOD (L3) data during the wildfires of 2010 were validated by AOD data obtained by the sun-sky photometer CIMEL, operating at the AERONET station Zvenigorod. The rates of radiative heating of the smoky atmosphere over ER and WS were also estimated and compared with the existed temperature anomalies, obtained using National Centers for Environmental Prediction National Center for Atmospheric Research reanalysis data. Optical and microphysical properties of smoke aerosols during the wildfires in ER and WS also revealed some similar characteristics. The aerosols were mostly found in the submicron-size fraction and characterized by very high single-scattering albedos (0.95–0.98). In the dense smoke conditions, the degree of linear polarization at the scattering angle 90° during both the events decreased to negative values ranging between ?0.1 and ?0.15. The optical properties of smoke aerosols were mainly conditioned by unusually narrow particle size distribution.     

Satellite remote sensing of total herbaceous biomass production in the senegalese sahel: 1980–1984

NOAA-6 and NOAA-7 1-km and 4-km advanced very high resolution radiometer data were obtained at frequent intervals during the 1980, 1981, 1982, 1983, and 1984 rainy or growing seasons in the Sahel zone of northern Senegal. Above-ground herbaceous biomass clippings, visual estimates, and hand-held radiometer measurements of herbaceous vegetation were made during and at the conclusion of the rainy seasons for 4 of the 5 years. The satellite data were compared to sampled above-ground biomass data and the integral of the satellite data over time was compared to end-of-growing-season above-ground total dry biomass. A strong correlation between the integrated NOAA-7 satellite data and end-of-season above-ground dry biomass was found for ground samples collected over a 3-year period. The satellite data documented the highly variable precipitation regime in the Senegalese Sahel both within years and among years and suggest a direct method of monitoring Sahelian total herbaceous biomass production in areas where the percentage cover of woody species is less than 10%. Predicted average total dry biomass production was 1093 kg/ha for 1981, 536 kg/ha for 1982, 178 kg/ha in 1983, and 55 kg/ha in 1984 for the $\text{～ 30,000 km}{}^2$ study area.     

Satellite remote sensing of total dry matter production in the Senegalese Sahel

Nine predominately cloud-free NOAA-7 advanced very high resolution radiometer images were obtained during a 3-month period during the 1981 rainy season in the Sahel of Senegal. The 0.55–0.68- and 0.725–1.10-μm channels were used to form the normalized difference green leaf density vegetation index and the 11.5–12.5-μm channel was used as a cloud mask for each of the nine images. Changes in the normalized difference values among the various dates were closely associated with precipitation events. Six of the images spanning an 8-week period were used to generate a cumulative integrated index. Ground biomass samplings in the 30,000 km² study area were used to assign total dry biomass classes to the cumulative index.     

Appendum to `Multiple-valued logic: a tutorial and appreciation'(April 1988 17-27)

The commenter points out a possible error in the section on storage techniques in the above mentioned article (see ibid., vol.21, p.17-27, April 1988). He explains why the error was made     

A bibliography on digital and computational convexity (1961-1988)

A bibliography of 370 references of books, papers in serial journals, and conference papers, on convexity in relation to computer science is presented. The subject is divided into five topics: (1) convexity and straightness in digital images; (2) convex hull algorithms and their complexity; (3) other computational problems related to convexity; (4) miscellaneous applications; and (5) general mathematical sources. These references range in time from 1961 to September 1988     

Synergistic use of orbital satellite image and ground-based information in environmental monitoring of railway alignment construction - a case study

Environmental monitoring of road/railway/highway alignment construction activity is necessary to assess the probable negative impacts on the physical, biological and hydrological environment. This would aid in assessing the effectiveness of mitigation measures proposed and executed measures. Multitemporal orbital remote sensing data along with site-based information on water and air quality and noise level were used in the environmental impact assessment (EIA) and auditing of Konkan railway alignment in India. This method of integrated data collection and analysis could be used effectively for monitoring similar projects elsewhere.     

Probabilistic assessment of loss in revenue generation in demand-driven production

In Demand-driven Production with Just-in-Time inputs, there are several sources of uncertainty which impact on the manufacturer??s ability to meet the required customer??s demand within the given time frame. This can result in a loss of revenue and customers, which will have undesirable impacts on the financial aspects and on the viability of the manufacturer. Hence, a key concern for manufacturers in just-in-time production is to determine whether they can meet a specific level of demand within a given time frame, to meet the customers?? orders and also to achieve the required revenue target for that period of time. In this paper, we propose a methodology by which a manufacturer can ascertain the probability of not meeting the required demand within a given period by considering the uncertainties in the availability of production units and raw materials, and the loss of financial revenue that it would experience as a result.     

Estimating crop yields and production by integrating the FAO Crop Specific Water Balance model with real-time satellite data and ground-based ancillary data

An operational crop yield model was developed by introducing realtime satellite imagery into a Geographical Information System (GIS) and the Crop Specific Water Balance (CSWB) model of the Food and Agriculture Organization (FAO). Input databases were developed with three different resolutions; agro-ecological zone (AEZ) polygons, 7.6 km and 1.1 km pixels; from archived satellite data commonly used by Early Warning Systems (EWS) to simulate maize yield and production in Kenya from 1989 to 1997. Simulated production results from the GIS-based CSWB model were compared to historical maize production reports from two Government of Kenya (GoK) agencies. The coefficients of determination (r ²) between the model and GoK district reports ranged from 0.86 to 0.89. The results indicated the 7.6 km pixel-by-pixel analysis was the most favorable method due to the Rainfall Estimate (RFE) input data having the same resolution. The GIS-based CSWB model developed by this study could also be easily expanded for use in other countries, extended for other crops, and improved in the future as satellite technologies improve.