The workshop on "Field observations for the Low-level Jet field experiment", which officially began Friday, February 8th, and which finished Saturday night, February 16th, was intended to introduce the participants to many aspects of the observational campaign planned for later this year. The workshop was a blend of practice in making meteorological observations and lectures covering a range of topics related to meteorological measurements, field experiments, and the processing of meteorological information. Considerable time was set aside for discussing the daily observations that were made, and the class was divided into two groups, each responsible for preparing recommendations on the design of the East-Andean Low-level jet field experiment (hereafter called ALLS) sounding network and the ALLS special raingauge network.
A total of 37 participants and 3 instructors formed the workshop (Table 1). Several of the Bolivian participants came with their own financial support.
The most difficult aspect of the workshop was the long bus trip to and from San Ignacio. Two buses were rented, each carrying close to 20 individuals. The road varied from reasonable pavement near Santa Cruz, to narrow bridges shared with the railroad, to potholed pavement, and finally to a stretch of dirt road that lasted for too-many hours. Despite this long drive, through terrain that was scarcely inhabited, the small town (mostly without paved roads) of San Ignacio had a 5-star hotel which nearly all participants agreed was excellent. Three pre-paid buffet meals per day allowed all participants to eat together, avoiding the usual mealtime dispersal of participants that occurs at most normal conferences.
The hotel had the major advantage of being only a 10 minute walk from the airport, where the observations were made. Only 1-2 small planes visited the airstrip during the week we were there - but one forcing a rapid removal of a theodolite that was following a balloon from the center of the runway! Thus, there was essentially no interference from aircraft at the observation site. One half the participants made morning observations from approximately 6:00 - 8:30 AM, while the other group made afternoon observations between 3:30 and 6:00 PM. Between these hours there were lectures or group work, with time off for lunch. In the evening, a discussion of the day's observations was held - this lasted anywhere from 30 min to 90 minutes or more. On the last (Saturday) night, after dinner, most of the group walked to the airport to close the workshop with a ceremonial night-time pilot balloon observation. This was actually useful training, and three groups followed the light for about 25 minutes, convincing everyone that it is feasible to make night-time pilot balloon observations!
The three main observational activities were:
1) establishment of a simple raingauge network around San Ignacio, along
the road networks around the town. Twenty four raingauges were installed
and monitored on a daily basis by a team each morning (as well as having
observers living at each site trained to make the observations). The network
provided interesting daily rainfall data that helped describe the large
spatial variability that can be expected from convective rainfall in the
tropics; the experience should help participants with future raingauge
deployment strategies. Most participants are probably convinced that it
is quite possible to set-up raingauge networks almost anywhere there are
rural populations, though there is considerable effort involved in doing
2) pilot balloon observation practice, with ~ 4 launches per day (2 in morning and 2 in afternoon). Two theodolites were available for this practice. A total of ??? 30gm pilot balloon observations were made during the workshop. Double-theodolite measiurements of 6 pilot balloon ascents were made to determine the acent rate of the balloons. Fortunately (!) the results showed that average ascent rate of the balloons was very close to that used in the PACS-SONET (3.7 m/s for heliunm filled balloons).
3) radiosonde preparation and launching practice, with observers following the balloon as well with one theodolite. One theodolite was available for this activity (different than those in #2). A total of 12 radiosonde launches were carried out during the workshop. The radiosonde system brought fromNSSL functioned well for the most part (but without humidity data except for one sonde, due to a compatibility problem with the sondes we were using and the radiosonde processor, but the temperature data was examined in class in some detail by the participants.
The workshop in San Ignacio appeared to have gone well, with most of the observational training objectives having been met. The objective was not to train to an expert level the participants, but rather to convince them that these activities are genuinely feasible. . Quite a few participants actually grew to enjoy the activity.
This web site shows some of the key results, as well as photos of the