XXII ISPRS Congress 2012: Technical Commission VII

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Multivolume work

Persistent identifier:: 1663813779

Title:: XXII ISPRS Congress 2012

Sub title:: Melbourne, Australia, 25 August-1 September 2012

Year of publication:: 2013

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663813779

Language:: English

Additional Notes:: Kongress-Thema: Imaging a sustainable future

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Document type:: Multivolume work

Volume

Persistent identifier:: 1663821976

Title:: Technical Commission VII

Scope:: 546 Seiten

Year of publication:: 2013

Place of publication:: Red Hook, NY

Publisher of the original:: Curran Associates, Inc.

Identifier (digital):: 1663821976

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(39,B7)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist ermittelt.; Literaturangaben

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

Corporations:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Adapter:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Founder of work:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Other corporate:: International Society for Photogrammetry and Remote Sensing, Congress, 22., 2012, Melbourne; International Society for Photogrammetry and Remote Sensing

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: [VII/1: PHYSICAL MODELLING AND SIGNATURES IN REMOTE SENSING]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: GEOSTATISTICAL ANALYSIS OF SURFACE TEMPERATURE AND IN-SITU SOIL MOISTURE USING LST TIME-SERIES FROM MODIS M. Sohrabinia, W. Rack and P Zawar-Reza

Document type:: Multivolume work

Structure type:: Chapter

International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012 XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 10 Rainfall (mm) 1. 2;,3 4.5 6.7.8 9 41; 43 :15- 17 Time (days) 19 21 Figure 3: daily rainfall in Birdlings Flat site during Nov. 2011 time-series of SM for the same period. To reveal the suspected non-linearity in the relationsship between the two parameter, non- linear regression analysis also used in the calculation, which did not provide any improvement in the results. This indicated that the relationship between LST and SM is more complicated and needs more careful data analysis. The same complication is vis- ible when the single time-series of SM are considered (Fig. 2). Therefore, time-series of SM were divided into two series namely day and night series to capture the unique variations of SM in warmer and often drier daylight hours compared to cooler con- ditions of the night. Nevertheless, no significant improvement achieved from the correlation of day or night series save few cases (e.g., Barren LC type both day and night). As a consequence, time-series were broken into smaller periods. 4.3 Correlations between subsets of LST and SM time-series following rainfall events Considering time-series of SM, break-points were chosen based on the higher points visible in the trends to overcome the sud- den effects of rainfall events. These higher points, as discussed earlier, correspond to rainfall events (see figures 2(a) and 2(b)), therefore, the expected normal SM and surface temperature trend is significantly interfered by these events. The challenge in this method was the limited available observations from MODIS LST, which is limited to four observations in clear and cloudless days. No significant improvement was observed in the correlations be- tween combined daily time-series, however, separate time-series of day and night showed considerable improvements (see Ta- ble 2). In this case the inverse correlations can be interpreted from the negative Pearson's r values. Except for the daily time- series of ‘Irrigated Crop’, all the cases have shown an inverse cor- relation between MODIS LST and the in-situ SM data. The dif- ference between day and night series correlation with that of the combined daily time-series is significant. As a result, it seems the relationship between LST and near surface SM varies from day to night, and a change in the direction of the correlation cannot be ruled out. This lead to an assumption of a nonlinear correlation between the two parameters. Hence, a non-linear (or curvilinear) correlation (NLC) fit with a quadratic model was used to calcu- late correlations between the two parameters. However, except for few cases, there was no considerable change in the correla- tion results (see Table 2, second column). Even though corre- lations for the separate day and night series have increased, the results still are not substantial. This means the variations in the two variable happen even in smaller time-frames. Considering time-series of LST (Fig. 2(b)), largest variations in surface tem- perature happen about every 12 hours. This can be a clue to look for a higher inverse correlation between LST and SM from the 20 LC Type r-daily NLC r-daily r-day r-night Open Grass 0.12 0.12 .—0.51 -025 Forest =0;17 —-0.18 -054 -—0.11 Irrigated Crop 0.01 0.01 -022 —037 Mixed Grass —0.05 —0.06 —0.33 - —0.29 Barren —0.05 —0.04 -0.10 -0.37 Table 2: Pearson’s r values from correlation of LST vs. in-situ SM after rainfall event on 21° Nov. to 1?* Dec. 2011 over vari- ous LC types LC Type r-daily 7-day r-night Open Grass —0.70 0.31 -0.93 Forest —0.27 0.68 —0.74 Irrigated Crop — —0.58 043 -048 Mixed Grass —0.67 —0.54 —0.68 Barren =0.59 —0.52. —0.88 Table 3: Pearson's r values from correlation of in-situ surface temperature vs. in-situ SM based on data from 21?* of Nov. 2011 over various LC types time-series of a single day. Therefore, breaking down the time- series to even smaller intervals could be one option to further increase the correlations, however, as mentioned before, there are not enough observations from the MODIS LST for a single day (or even a few days). As a consequence, correlations calculated using the in-situ measured surface temperature and SM data for a single day is discussed in the next section. 4.4 Correlations between in-situ surface temperature and SM for a single day In this section correlations between surface temperature and near- surface SM in-situ data, both with 30 minute rate, from a sin- gle day are presented. As the previous sections, correlations are based on the combined daily time-series as well as the separated day and night series. Combined daily time-series from all the LC types showed significant improvement in the correlations (see Ta- ble 3, first column). Day series correlations are ambiguous, some of the LC types showed positive while the other LC types showed relatively strong inverse correlations. Finally, the night series showed strong inverse correlations for all the LC types. Some of the LC types, such as forest and the irrigated site, showed lower correlations which seems is due to the unusual distribution of heat or moisture on the soil under the effects of the canopy. 5 CONCLUSIONS AND FUTURE WORK In this paper time-series of MODIS LST product, which is a ther- mal remote sensing dataset, was compared with the in-situ SM data over various LC types in Canterbury Plains in New Zealand. Correlations between time-series of the two parameter for the month of November (2011) showed insignificant agreement. There- fore, time-series were broken down to day and night series to capture possible trends from cool and warmer hours separately. Nonetheless, correlations were not significant even with data from smaller time-frames. Lack of continuous observations for a day from the MODIS product restricted a diurnal analysis using this dataset, therefore, only in-situ data were used for a single day (as well as two 12 hours periods for day and night). The agreements between a single day time-series were significant. These results indicated that patterns of the relationship between SM and LST vary during a 12 to 24 hours period, and cannot be captured using longer time-series of the two variable. Similar results have been

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