High-Resolution Image

For 2006, the ARM Mobile Facility is stationed at Niamey, Niger, on the edge of the Sahara Desert, participating in the African Monsoon Experiment (AMMA). On March 29, 2006, a 90 percent solar eclipse occurred. The top portion is the Meteosat visible (0.6 microns) image, which shows the shadow of the Moon on the Earth at the time of eclipse maximum at Niamey. The bottom portion shows the shortwave downfluxes measured during the eclipse, with a prominent dip to near zero flux just after 9 am. The purple curve is the direct solar beam. The blue line shows the diffuse flux, which is quite large because there are some high clouds moving across (hence the wiggles), but also because there was a dust storm, the second of the year although not as thick as the first one in early March. The yellow and black curves show different methods of getting the total downward flux (direct plus diffuse). Note that Niamey is at 2 degrees east longitude, thus local time is the same as UT (=GMT).

(Submitted by Warren Wiscombe, ARM Chief Scientist)