AHN en technologische ontwikkelingen

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1 Split by PDF Splitter AHN en technologische ontwikkelingen Ramon Hanssen Mathematische Geodesie en Puntsbepaling, TU Delft

2 AHN1, AHN2, en dan verder? Wat gebeurt er om ons heen? Wat is de volgende stap? Welke Δ is nu nodig? Meer punten/ hogere ruimtelijke resolutie? Betere hoogteprecisie? Korter herhalingsinterval? Andere parameters??? Conclusies

3 Behoefte aan hoogtemodellen!

4 Topografie van de aarde: goed bekend?

5 Topografie van Mars (MOLA, 1997)

6 Topografie Aarde versus Mars Ocean floor Mid-Atlantic ridge Ship soundings and radar altimeter Horiz res 15 km Mars Valles Marineris MOLA laser altimeter Horiz res 1 km Vert prec 250 m Vert prec 1 m We kennen de topografie van Mars, Venus en de Maan beter dan die van de Aarde! Source: Oceanography, vol 17, 1, 2004

7 Digitale hoogtemodellen DEM Corona: 144 satellieten (1959 and 1972) Vrijgegeven in 1995 Resolution tot 1.8 m 14x188 km2 : 18 USD

8 Digitale hoogtemodellen (DEM) GTOPO30 30 arcsec = 1 km ruimtelijk Bron: verschillende topografische bestanden Nauwkeurigheid: Afhankelijk van bronbestand Sigma ~ m vrij beschikbaar

9 SRTM, C-band SRTM C-band 3 arcsec = 90 m ruimtelijk Bron: Shuttle Radar Bedekking: ~80% van landmassa Nauwkeurigheid: Sigma ~7-8 m vrij beschikbaar

10 ASTER GDEM ASTER 15 m ruimtelijk Bron: Stereo optisch Bedekking: ~99% van landmassa Nauwkeurigheid: Sigma ~10 m, maar variabel vrij beschikbaar

11 SRTM-X SRTM X-band 25 m ruimtelijk Bron: Shuttle Radar Bedekking: inhomogeen Nauwkeurigheid: Sigma ~6 m vrij beschikbaar

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13 TanDEM-X TanDEM-X 12 m ruimtelijk Bron: Satelliet radar Bedekking: ~99% van landmassa Nauwkeurigheid: Sigma ~1 m vrij beschikbaar

14 Meetconcept: Helix baan

15 TanDEM-X voorbeeld 12 meter posting, 2 meter relatieve hoogteprecisie (90%)

16 TanDEM-X DEM products Ruimtelijke resolutie 1 m 3 m 10 m 30 m 100 m 300 m Laser altimetrie (Airborne) m Radar SAR (Airborne) Fotogrammetrie (Airborne) TanDEM-X (2) m TanDEM-X (1) 1-5 m HR satelliet INSAR-ERS SPOT m SRTM-C (USA) ASTER SRTM-X m SRTM-C GTOPO30 >20 m Bedekking in miljoen km2

17 AHN1, AHN2, en dan verder? Wat gebeurt er om ons heen? Wat is de volgende stap? Welke Δ is nu nodig? Temporele update? Meer punten/ hogere ruimtelijke resolutie? Betere hoogteprecisie? Andere parameters???

18 De nieuwe Delta : Temporele update? Nut en noodzaak hangt af van: Fysisch proces (verandert de hoogte? Hoe snel in de tijd?) Is dit relevant (toepassingsvraag) Meetprecisie (kunnen we meten wat we willen?) Keuze techniek

19 De nieuwe Delta : Puntdichtheid? 0.5 m voldoende? Nut en noodzaak hangt af van: Fysisch proces ( hoogtegladheid?) Is dit relevant? (toepassingsvraag) Meetprecisie (kunnen we meten wat we willen?) Keuze techniek

20 De nieuwe Delta : Hogere precisie? Nut en noodzaak hangt af van: Fysisch proces (welk proces heeft signaal <sigma?) Is dit relevant? (toepassingsvraag) Keuze techniek

21 De nieuwe Delta : Andere parameters? Hoogte? of mutaties? Hoogte of hoogte? Orthometrisch of geometrisch Absoluut of relatief? NAP of locaal stelsel? Hoogteveranderingen (temporeel)

22 Hoogte of mutaties? Mutaties: Alternatieven door radarsatellieten (herhalingsfrequentie van dagen-weken, resolutie in orde van meters, gratis)

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24 Split by PDF Splitter 92/4-93/11 95/4-97/1 97/4-99/7 99/10-02/4 Regio Almere vanuit satelliet radar perspectief April 92November 93 April 95January 97 April 97July 99 October 99April

25 Split by PDF Splitter 92/4-93/11 95/4-97/1 97/4-99/7 99/10-02/4 Regio Almere vanuit satelliet radar perspectief April 92November 93 April 95January 97 April 97July 99 October 99April

26 De nieuwe Delta : Andere parameters? Hoogte? of mutaties? Hoogte of hoogte? Orthometrisch of geometrisch Absoluut of relatief? NAP of locaal stelsel? Hoogteveranderingen (temporeel)

27 Orthometrische of geometrische hoogte? h = H + N Gemiddeld zeeniveau GPS, laser, radar Zwaartekracht waterpassing h P Q N P O H Loodlijn Ellipsoide Geoide NAP Zee h (Ellipsoidische hoogte) = Afstand op ellipsoide (Q-P) N (Geoide hoogte) = Afstand op ellipsoide (Q-P O ) H (Orthometrische hoogte) = Afstand langs loodlijn (P O - P)

28 NLGEO2004 [m] t.o.v. GRS80 (ETRS89/WGS84) Precisie (sigma) op cm niveau ~10 jaar houdbaar Applicatie-afhankelijk Update van AHN ivm absolute hoogte vergt update van geoide!

29 De nieuwe Delta : Andere parameters? Absolute hoogte of relatieve hoogte?

30 IPCC AR4, hoofdstuk 12, pagina Current adaptation and adaptive capacity It is apparent that climate variability and change already affects features and functions of Europe s production systems (e.g., agriculture, forestry and fisheries), key economic sectors (e.g., tourism, energy) and its natural environment. Some of these effects are beneficial, but most are estimated to be negative (EEA, 2004b). European institutions have recognised the need to prepare for an intensification of these impacts even if greenhouse gas emissions are substantially reduced (e.g., EU Environmental Council meeting, December 2004). The sensitivity of Europe to climate change has a distinct north-south gradient, with many studies indicating that southern Europe will be more severely affected than northern Europe (EEA, 2004b). The already hot and semi-arid climate of southern Europe is expected to become warmer and drier, and this will threaten its waterways, agricultural production and timber harvests (e.g., EEA, 2004b). Nevertheless, northern countries sea-level are also sensitive rise to climate and change. river flooding because 55% of its territory is The below Netherlands sea is an level example where of a country 60% highly of susceptible its population to both sea-level lives rise and and river flooding 65% because of its 55% of its territory is below sea level where 60% of its population lives and 65% of its Gross National Gross Product (GNP) National is produced. Product As in other (GNP) regions, natural is produced. ecosystems in Europe are more vulnerable to climate change than managed systems such as agriculture and fisheries (Hitz and Smith, 2004). Natural ecosystems usually take decades or longer to become established and therefore adapt more slowly to climatic changes than managed systems. The expected rate of climate change in Europe is likely to exceed the current adaptive capacity of various non-cultivated plant species (Hitz and Smith, 2004). Sensitivity to climate variability and change also varies across different ecosystems. The most sensitive natural ecosystems in Europe are located in the Arctic, in mountain regions, in coastal zones (especially the Baltic wetlands) and in various parts of the Mediterranean (WBGU, 2003). Ecosystems in these regions are already affected by an increasing trend in temperature and decreasing precipitation in some areas and may be unable to cope with expected climate change. The Netherlands is an example of a country highly susceptible to both The possible consequences of climate change in Europe have stimulated efforts by the EU, national governments, businesses, and Non-Governmental Organisations (NGOs) to develop adaptation strategies. The EU is supporting adaptation research at the pan-european level while Denmark, Finland, Hungary, Portugal, Slovakia, Spain and the UK are setting up national programmes for adapting to climate change. Plans for adaptation to climate change have been included in flood protection plans of the Czech Republic and coastal protection plans of the Netherlands and Norway.