Remote sensing for resources development and environmental management: Remote sensing for resources development and environmental management

Damen, M. C. J.

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Multivolume work

Persistent identifier:: 856342815

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856342815

Language:: English

Additional Notes:: Volume 1-3 erschienen von 1986-1988

Editor:: Damen, M. C. J.

Document type:: Multivolume work

Volume

Persistent identifier:: 856343064

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Scope:: XV, 547 Seiten

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856343064

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(26,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Damen, M. C. J.

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: 1 Visible and infrared data. Chairman: F. Quiel, Liaison: N J. Mulder

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: Processing of raw digital NOAA-AVHRR data for sea- and land applications. G. J. Prangsma & J. N. Roozekrans

Document type:: Multivolume work

Structure type:: Chapter

65 >.065 * T b 5-17.255 0.094 * T b 5 -25.11 ■ees kelvin) I on a linear I channel 2 albedos. ition nvolves assigning a 'Oint in the vigation results, ite must be known then giving the pixel (in lishes every other ational NOAA- e used together nline to determine lite-point in this s of the pixels on gational grid can can be resampled E TEMPERATURES three (or two) are being used to atures. The and land surface D asurements of the pace. Nevertheless aan be eliminated, a emissivity of sea stant, radiometric an account of the temperatures near Ltu measurements is by far the largest .ns in the 'rection. The infra-red channels lat atmospheric lannel. The "window" is rapour ■tical near combination the number of mined, empirically imum performance ditions believed rticular area, or he correct is critical for from satellites, e North East determined by a Laboratory in the coefficents are ime the "split"- ue must be used, nergy in channel 3 triple" window ults provided Figure 2: Location of the in situ stations used in verifi cation study. department of KNMI has performed some in-situ measurements on the North Sea. "Bucket"- temperatures are menasured at ± 30 stations (see fig. 2). These measurements are compared with AVHRR derived SST's. The date of the NOAA-9 image was October 25, 3-00 GMT. The in-situ measurements started on October 28, 15.00 GMT and ended on the 30 th , 5.00 GMT. The SST's were also calculated using coefficients determined by McClain (1981). Figure 2 shows the in-situ measurements along with the two different satellite SST's retrievals. This graph shows that the in-situ spatial structure is well represented by the satellite derived SST's and also that the Rutherford coefficients perform slightly better than the McClain coefficients. The difference between in-situ measurements and satellite derived SST is never larger then 0.55 for the Rutherford coefficients: the mean bias being -0.064 and the RMS 0.244. For the Mcclain coefficients the statistics are: max. difference is 0.73; mean bias is 0.022 and RMS 0.292. These statistics are in good agreement with published results (Minnett et al, 1984). 4.2. Land surface temperature (LST) 4.2.1. Techniques For the development of a method to derive LST's out of AVHRR-thermal IR-data two more problems, except for the atmospheric correction arise: 1. the variable emissivity of land surface. 2. Lack of suitable groundtruth data. Price (1984) has demonstrated that the use of split window techniques originally developed for SST's, can also be used for the calculation of true LST's. He estimated a 2-3 K error in the estimates of LST's, using a SST- split window technique mainly caused by uncertainties ih the emissivity small compared to satellite-observed temperature variations in a certain region. t s (c) Î : in situ "bucket" temperatures » « * split window SST (Rutherford coefficients) • « : Ü „ „ (McClain „ ) Figure 3: Results of verification study for split window SST's. Oxford, U.K. we investigated the relation between split-window LST's and "screen"-temperatures, measured at meteorological stations. A data-set (day and night NOAA-9 imagery and meteorological data of the same times) for the period 14-20 April 1985 was used. The stations involved are nearly all located in the U.K.. LST was calculated, using the Rutherford coefficients. It must be added that in general, differences between screen- and land surface temperatures will depend heavily on the actual weather conditions, the nature of the underlying surface and the type of vegetation cover. This makes the relation rather complicated and variable in space and time. The situation is still further complicated by the fact that the screen temperature measurements are point measurements whereas the LST's are representive for an area of approx. 1x1 km . this all renders the correlation between the two temperatures rather poor (regression coefficient 038). However byaveraging the surface- and air temperatures, of all cloudfree stations at a certain date, it can be shown that the average difference between surface- and screentemperature is fairly steady from day to day (see fig. 4). 5. CONCLUSIONS - Digital AVHRR-imagery can suitable be processed in an automatic way to provide Earth-surface parameters. - The development of the "channel 4- channel 5"- technique turned out to be a valuable addition to available cloud clearing algorithms identifying thin cirrus clouds litherto going undetected. - Limited research at KNMI has demonstrated that the AVHRR can deliver relatively accurate surface temperatures (especially for sea surface), suitable for use in various applications. - KNMI now has as the only institute in the Netherlands the software available to perform all the necessary steps in the automatic processing of AVHRR-imagery. REFERENCES Research 4.2.2. Validation In co-operation with the Met. Office Unit in Harries, J.E.,Llewellyn-Jones, D.T., Minnett, P.J., Saunders, R.W. and Zavody, A.M., 1983. Observations of sea-surface temperature for

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