The MISU Atmospheric Physics Group

The MIDAS/DROPPS Campaign Andøya, Norway, June-July 1999

Objectives

In Summer 1999, scientists from the USA, Norway, Germany, Sweden and Austria participated in the MIDAS/DROPPS campaign at Andoya, Norway. The campaign addressed dynamical and physical parameters of Noctilucent Clouds (NLC) and Polar Mesosphere Summer Echoes (PMSE). The origin of PMSE, their proposed relationship to dust and aerosol particles and to NLC are among the most important questions governing the physics of the polar summer mesosphere.

From July 4 to July 16, twenty scientific rocket payloads were launched, closely coordinated with ground-based optical, radar and lidar measurements. Several experiments concerned the distribution of particles in the high latitude summer mesosphere, the electrodynamic environment there, and their complex relationship to PMSE and NLC. Special emphasis was also paid to small scale structures in the neutral and ionised atmosphere and their relation to PMSE.

A summary of the experiments involved in the campaign is given in the tables below.
 

MISU Instrumentation

The MISU Atmospheric Physics group took part in the campaign with rocket-borne photometers and particle detectors. These instruments were flown on two NASA payloads denoted as DROPPS (= Distribution and Role Particles in the Polar Summer Mesosphere using Co-ordinated Rocket, Radar, and Lidar techniques). For each DROPPS payload, MISU contributed

• two narrow band photometers (220 nm and 450 nm) for the detection of scattered sunlight
• one broadband optical sensor (250-500 nm) for scattered sunlight (SLIPS)
• two electrostatic probes for the detection of impacting particles (PAT)

All five instruments provided information about the vertical structure and the particle properties of the PMSE/NLC layers present.

The MIDAS/DROPPS campaign featured the first simultaneous measurement of NLC optical properties by rocket-borne photometers (220 nm and 450 nm) and ground-based lidar (532 nm). As in addition to the different wavelengths the photometers also covered a large range of scattering angles, a comprehensive optical data set has become available.

The MIDAS/DROPPS campaign also featured the first direct comparison of different particle impact measurement techniques.
 

Here are some pictures from the campaign . . .

Results

The DROPPS payloads flew as part of two major salvoes on July 5, 23:36:30 UT and on July 14, 3:28:45 UT.

The first salvo was launched into very strong and persistent PMSE. Also a weak NLC layer was detected by MISU's optical instruments. The second salvo was launched into a bright NLC display without simultaneous presence of PMSE.

The figure to the left illustrates the vertical structure of the two NLC layers. The profiles have been obtained as height derivitives of the photometer signal at 450 nm.

First results of the campaign have been presented at AGU, COSPAR and several workshops. A special section in Geophysical Research Letters is currently in preparation.
 

Participants

Here is a list of the experiments and scientific groups involved in the MIDAS/DROPPS campaign. More information can be found on the homepage of Andoya Rocket Range (check under Completed Campaigns).
 
 

The DROPPS payloads

The MIDAS payload

Other Rocket Experiments

Ground-Based Measurements

	The Atmospheric Physics Group The Department of Meteorology at Stockholm University
Jörg Gumbel, gumbel@misu.su.se, 1999-12-23