Capability of airline jets as an observation platform for noctilucent clouds at middle latitudes

Hidehiko Suzuki,Peter Dalin,Ayako Matsumoto,Satoshi Ishii,Yuriko Nakamura,Yuta Hozumi,Kazuyo Sakanoi,Takuo T Tsuda,Kaori Sakaguchi,Taku Takada

doi:10.1186/s40645-022-00469-4

Abstract

The exact occurrence frequency of noctilucent clouds (NLCs) in middle latitudes is significant information because it is thought to be sensitive to long-term atmospheric change. We conducted NLC observation from airline jets in the Northern Hemisphere during the summer 2019 to evaluate the effectiveness of NLC observation from airborne platforms. By cooperating with the Japanese airline All Nippon Airways (ANA), imaging observations of NLCs were conducted on 13 flights from Jun 8 to Jul 12. As a result of careful analysis, 8 of these 13 flights were found to successfully detect NLCs from middle latitudes (lower than 55° N) during their cruising phase. Based on the results of these test observations, it is shown that an airline jet is a powerful tool to continuously monitor the occurrence frequency of NLCs at midlatitudes which is generally difficult with a polar orbiting satellite due to sparse sampling in both temporal and spatial domain. The advantages and merits of NLC observation from jets over satellite observation from a point of view of imaging geometry are also presented.

Highlights

Noctilucent clouds (NLCs) are the Earth’s highest clouds, and they appear at the mesopause region during summer in both subpolar regions (Gadsden and Schröder 1989)
This paper reports the results of NLC observations in the middle latitude region using airline jets
This paper focuses on NLC detections from latitudes lower than 55° N to discuss the actual occurrence of NLCs in middle latitudes (< 60° N)

Summary

Introduction

Noctilucent clouds (NLCs) are the Earth’s highest clouds, and they appear at the mesopause region during summer in both subpolar regions (Gadsden and Schröder 1989). The observation of PMCs from Geostationary Earth Orbit (GEO) meteorological satellite is reported (Tsuda et al 2018). This method is quite effective to continuously monitor the PMCs in both hemispheres. International jets fly at an altitude of about 10 km during the cruising phase From this altitude, NLC observation is possible without obstruction by lower clouds because most tropospheric clouds are below this altitude. This paper reports the results of NLC observations in the middle latitude region using airline jets. 2. Results of NLC observations by airline jets conducted in the Northern Hemisphere during the summer 2019 are shown in Sect. 3. Occurrence of NLCs in middle latitudes and the advantages of observation with jets are discussed in Sect.

Methods

Results

Discussion

Conclusion