Q&A_sidebar_000224 Egyptian-born geologist Farouk El-Baz, who helped pioneer the field of remote sensing, is one of many scientists who are eagerly awaiting data from the
STS 99 Shuttle Radar Topography Mission. Now the director of the Center for Remote Sensing at Boston University, El-Baz recently spoke with SPACE.coms Andrew Chaikin about he hopes to learn from STS 99s high-resolution, 3-D maps of Earth.SPACE.com: What are you looking forward to from this latest radar mission, STS 99?
El-Baz: There are really two very important pieces. One of them [is that we don't really know which way many], if not most, of these river channels are tilting. Are they going to the northeast or are they going to the southwest?
SPACE.com: Why is that important for you to know?
El-Baz: We want to know which way the water flowed. Have they come from the high plateau in Egypt and theyre heading toward Chad? Or have they come from Central Africa and heading toward the northeast, toward the Nile?
SPACE.com: If you found out which direction, what would the implications be?
El-Baz: We would know where the ground water from these rivers would be.
SPACE.com: Archaeologists are interested in figuring out the trade routes and the ways in which human beings would have migrated in the past. And if you want to know that, then you look for things like rivers. But youre saying that even today its important to know because you want to know where to find ground water.
El-Baz: Absolutely.
SPACE.com: And this will be higher resolution than youve had before?
El-Baz: Much higher, yes, because the 90-meter (295-foot) resolution will be fine for the [general] topography, but naturally Im going to fight tooth-and-nail to get the 30-meter (98-foot) resolution, because these tilts can be very slight. These tilts are tiny because the places are really flat and the [existing] maps cannot help us.
An image of White Sands, N.M. from STS-99.
SPACE.com: Youve also been involved in archeological work. Is this mission going to help with those studies?
El-Baz: Absolutely, because there is a site right now that is slated for agriculture in southern Egypt, land reclamation, called the Tushka depression. Its a very large depression. And we would like to use the radar data to know what the real shape of that depression was, to figure out where human beings may have lived.
SPACE.com: This depression was once a lake?
El-Baz: Yes.
SPACE.com: What time period are we talking about?
El-Baz: Could be 140,000 years ago. This is a time when supposedly the last migration from Africa into Europe occurred.
Knowing the exact shape of this depression would also allow us to create a kind of model for what is going to happen after this place is used in agriculture. Because the water that will be drained from the depression, after they use it in agriculture, will be dumped back in the middle.
There is another thing that is really important to us right now: We are working on an atlas of the dry valleys, or wadis, of Oman, specifically to mark areas that are dangerous for flash floods. We want to get some detailed information on the shape, and the tilt, and the widths, and changes of the width, of the wadis.
Last year six people died from flash floods in Oman. And in different areas.
The expatriates who live there love the country because it is beautiful. And on vacation days, they just get together in groups and head for the desert in their jeeps and four-wheel-drive vehicles. And they come down in the flats and they see this beautiful area, sunny and magnificent and there are a couple of trees that look like date palms or whatever, and they camp around them, and drink and be merry. And sleep overnight or sit all day and enjoy an outing in the desert. And have a cookout...
Unknown to them, there will be a cloud, some three, four hundred kilometers away, and it would rain somewhere on the high mountains. And the water would collect and come gushing down with a kind of
tsunami wave that is six feet (2 meters) tall, that can clobber them and their cars and their tents and so on. And we were asked by the government of Oman to do an atlas based on satellite images, and mark all of these dangerous locations. One of the things that can help us a great deal is to measure the amount of flow of the water based on the amount of rain that is expected from historical times, to see where the water would spread because it depends really on the width of the valley, and the tilt of the terrain, and the slope. So to get this information you would need radar interferometry.
SPACE.com: You mentioned youre going to fight tooth and nail to get the 30-meter resolution data. Do you anticipate any difficulty getting it?
El-Baz: We have been told that there is no access up until now.
SPACE.com: What would be the best resolution you have been told you would get?
El-Baz: 90 meters.
SPACE.com: What could you accomplish if you only got the 90-meter data?
El-Baz: Well do something in Egypt, I think. But we would not be able to do the studies in Oman.
SPACE.com: And how about the migration of 140,000 years ago?
El-Baz: We might be able to do something in there, too. But it will be a halfway effort. Because there are several archaeologists who are anxious to go and see what is there [at the Tushka depression]. But we cannot tell them, "Go and look around a 500-square-kilometer (193 square-mile) depression." We have to tell them "Go to point X."
SPACE.com: And you cant pin that down without the high-resolution data?
El-Baz: No, I dont think we can.
advertisement
