II. Background Information

SOP and IOPs: The field phase—also called "Special Observing Period" (SOP) lasted from 7 September to 15 November 1999. It consisted of 17 "Intensive Observing Periods" (IOPs), dictated by interesting weather developments and lasting usually a few days. During such IOPs, the available observing systems, including the aircraft, were deployed at an increased, often very intense rate, and rapid scans of the Meteosat were initiated. This report attempts to briefly describe all IOPs in consecutive order.

Scientific Objectives: Table 1 lists the internationally agreed upon scientific objectives. Four of these (marked by stars) represent the main scientific aims of the US program, which are emphasized in this report. In the following chapters, objectives P1-P3 will be called "Wet MAP" and P4-P8 "Dry MAP".

Target Areas, Operations Centers and Topography: Fig. 1 gives a map showing the locations of the scientific target areas, the three operations centers, and some of the geographical regions referred to in the body of this report. The primary operations center, called "MOC" (MAP Operations Center), was located at the airport in Innsbruck, Austria. The NCAR Electra, NOAA P-3 and UK C-130 were based there. A second operations center, called "POC" (Project Operations Center), was located at the airport in Milano-Linate, Italy.

The French Merlin and Fokker aircraft were based there. The third operations center, called "COC" (Coordination and Operations Center - Rhine Valley), was located in Bad Ragaz, Switzerland. The Dimona motorglider was based there. The DLR Falcon aircraft was operated out of Oberpfaffenhofen, Germany.

Atmospheric Conditions: As was expected from the beginning, favorable weather situations resulted in a "bunching" of practically all scientific objectives within a few days, since a cross-Alpine airflow (either from the north or from the south) has the potential of causing heavy precipitation or flooding on the upwind side of the Alps (corresponding to the "Wet MAP" objectives), while triggering foehn-related phenomena (corresponding to the "Dry MAP" objectives) on the downwind side.

Some interesting statistics of the 1999 events, prepared by Prof. Reinhold Steinacker (University of Vienna), bear out this "bunching" clearly (Table 2). His comparison of the 1999 SOP with the past 10 years (Table 3) indicates how favorably the atmosphere behaved in 1999, as some of the phenomena of interest occurred twice as frequently as in the climatological average.

Table 2. Calendar of weather phenomena favoring MAP scientific objectives (left) during 1999 SOP (Symbols refer to varying alpine regions). Note "bunching of atmospheric events. (Courtesy Reinhold Steinacker)

Statistics of MAP-related weather events (Courtesy of Reinhold Steinacker)

Number of days favoring various MAP scientific objectives (left) during 10 year mean as compared to 1999 SOP. Note high frequency of 1999 events.

Observing Systems: As Table 4 shows, the US provided some of the key observing systems to the MAP field phase; among them were NCAR’s polarimetric Doppler "S-Pol" radar, centerpiece of the ground-based radar array in the Lago Maggiore area (see Fig. 2), the two Doppler radar- and lidar-equipped turbo-prop aircraft (NCAR Electra and NOAA P-3), the NOAA scanning ground-based Doppler lidar installed between the Brenner Pass and Innsbruck (for gap flow) and the NOAA mobile "Doppler on Wheels" (DOW). With their arrival in the field, the US observing systems became part of the MAP international resources, serving all scientific objectives.

Figure 2. MAP Doppler radar array installed in the Lago Maggiore Target Area northwest of Milano, Italy.

a. NCAR Electra with Eldora and SABL (Lidar): 150 Research hours

(132 used)

b. NOAA P-3 with Doppler radar: 105 Research hours

(96 used)

c. NCAR/NASA GPS Dropsondes (225)

d. DLR Falcon 20 research hours

a. NCAR S-POL polarimetric Doppler radar: 7 Sept – 8 Nov

b. Univ. of Oklahoma Doppler on Wheels (DOW): 17 Sept – 6 Nov

c. NOAA scanning Doppler lidar 2 Oct – 14 Nov

d. U. of Washington OPRA radar (vertically pointing): 17 Sept – 15 Nov

 U.S. Funding Agencies and Project Personnel: The main funding agencies of the US, supporting both the PIs and observing systems, are shown in Table 5.

The US sent over 120 people into the field, including 60 from NCAR. They are listed in Appendix A, and represent about half of the international participation. Table 6a provides a list of the 13 participating countries.

This Report: Obviously the scientific results of MAP will not be known for some time. Nevertheless, we have attempted to provide some interesting pictorial examples to some of the main events and scientific objectives of interest. This report focuses more on the flexible than the fixed platforms, especially the missions of the seven participating aircraft (see Table 6b), since these are most variable during the many IOPs, and probably of primary interest to the scientific readers of this report.