Question

1. adler and hongs primary source of rainfall data is the tropical rainfall measuring mission (trmm), a joint nasa - japanese space agency mission that launched in 1997. adler said, there are two main things that trmm provides for this multi - satellite analysis. one, its the calibrator for the information from the other satellites. two, its always in the tropics, and gives us very good coverage in a critical area.
2. trmm orbits the earth from west to east along the equator, weaving between 35 degrees north and 35 degrees south. adler and hong collect data from other satellites that are in polar orbits, traveling north to south around the earth. because the trmm orbit crosses over the paths of each polar - orbiting satellite, were able to collect subsets of data from both satellites at the same time, adler said. we use trmm data, which we think is making the best estimate, to calibrate, or adjust the rain estimates from the other satellites.
3. to test whether their rainfall product accurately detected landslide - triggering rain events, adler and hong identified 74 rainfall - induced landslides that occurred between the trmm launch and 2006, including the guinsaugon slide. over the years, scientists have analyzed case studies of landslides to determine the intensity and duration of rainfall—usually measured at ground - based rain gauges—beyond which landslides become likely. adler and hong plugged their satellite - based rainfall data into equations that predicted when the rainfall at each landslide location would have reached the threshold. their results closely matched previous threshold estimates, confirming that satellite observations could detect the extremely intense rainfall needed to trigger the slides.

real - time applications

1. adlers and hongs satellite - based landslide - prediction products are available online and contain data from 2002 through the present. they are updated in real time, allowing anyone on the web to determine if an area is receiving particularly intense rainfall or if it has reached a critical level of accumulation.

part b
which quotation from the passage refines the central idea in part a?
\adler and hongs primary source of rainfall data is the tropical rainfall measuring mission (trmm), a joint nasa - japanese space agency mission that launched in 1997.\(paragraph 7)
\trmm orbits the earth from west to east along the equator, weaving between 35 degrees north and 35 degrees south.\ (paragraph 8)
\their results closely matched previous threshold estimates, confirming that satellite observations could detect the extremely intense rainfall needed to trigger the slides.\(paragraph 9)
\in remote, landslide - prone areas like leyte island, it can be difficult for emergency planners to assess landslide hazards in time to prevent disasters.\(paragraph 12)

Explanation:

To refine the central idea, we need a quote that supports or elaborates on it. The central idea likely pertains to the effectiveness of using TRMM data for rainfall - related analysis and its connection to landslide - triggering rainfall. The quote in paragraph 9 about results matching previous estimates and confirming satellite observations' ability to detect intense rainfall for landslides best refines the idea as it shows the accuracy and utility of the data.

Answer:

C. "Their results closely matched previous threshold estimates, confirming that satellite observations could detect the extremely intense rainfall needed to trigger the slides." (paragraph 9)