INFERRING SURFACE HEAT FLUX DISTRIBUTIONS2
We present a method that uses a global seismic model of the crust and upper mantle to guide the extrapolation of existing heat ow measurements to regions where such measurements are rare or absent. For any chosen spatial point on the globe, the procedure generates a histogram of heat ow values deter...
| Main Authors: | , , |
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| Format: | Text |
| Language: | English |
| Published: |
2003
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| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.399.5187 http://ciei.colorado.edu/geophysics/pubs/mhrpubs/pubs/2003/1.pdf |
| Summary: | We present a method that uses a global seismic model of the crust and upper mantle to guide the extrapolation of existing heat ow measurements to regions where such measurements are rare or absent. For any chosen spatial point on the globe, the procedure generates a histogram of heat ow values determined from existing measurements obtained from regions that are structurally similar to the target point. The inferred historgrams are based on a \structural similarity functional", which is introduced to quantify the structural analogy between di erent regions. We apply this procedure world-wide using the global heat ow data base of Pollack et al. [ 1] guided by an update of the 3-D shear velocity model of the crust and uppermost mantle of Shapiro and Ritzwoller [ 2]. The method results in an inferred probability distribution for the heat ux for each geographical region of interest. These distributions are strongly non-Gaussian, but are well approximated by the log-logistic distribution which is completely speci ed by two parameters. The inferred distributions agree well with observed distributions of heat ux taken in 300 km radius circles regionally in numerous locations. Particular attention is drawn to the inferred surface heat ux distributions across Antarctica, where direct measurements are rare but information about heat ow may be needed to help understand the dynamics of the Antarctic ice sheets and ice streams. Mean heat ow in West Antarctica is expected to be nearly three times higher than in East Antarctica and much more variable. This high heat ow may a ect the dynamics of West Antarctic ice streams and the stability of the West Antarctic Ice Sheet. 3 1. |
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