From Operational Ceilometer Network to Operational Lidar Network

Mariana Adam,Joelle Buxmann,Myles Turp,Carlos Ordóñez,Jacqueline Sugier,Andrew Horseman

doi:10.1051/epjconf/201611927007

Abstract

During the eruption of Eyjafjallajokull in 2010, the Met Office ceilometers (Laser Cloud Based Recorders - LCBR) provided reasonable information about volcanic ash plumes over the United Kingdom [1]. This capability triggered the development of an operational system to provide quick looks of the range corrected signals (RCS ) in near-real-time (NRT). Moreover, the Met Office acquired eleven Jenoptik ceilometers to supplement the operational ceilometer network. The combined network became operational in 2012 and currently comprises a total of 43 ceilometers reporting backscatter profiles in NRT. In 2013, Civil Aviation Authority (CAA) and the Department for transport (DfT) sponsored the acquisition of 9 fixed lidars and one mobile unit (each accompanied by a sunphotometer), to further improve the quantitative monitoring of volcanic ash. The current status of both ceilometer and lidar/sun-photometer networks is discussed and further developments are proposed.

Highlights

The Met Office hosts and runs the London Volcanic Ash Advisory Centre (VAAC) as part of the nine VAACs worldwide
The VAAC forecasters produce volcanic ash advisories and guidance products using a combination of various observation of volcanic plume [2]
The ground-based observations in the UK are currently provided by the ceilometer network and by the end of 2016 by the VA network (Lidar and sun-photometer network for Volcanic Ash observations)

Summary

MET OFFICE CEILOMETER NETWORK

The Met Office ceilometer network includes 32 Vaisala (25 of CL31 and 7 of CT25k) and 11 Jenoptik (Nimbus) ceilometers. Most of CT25k were replaced with CL31 during 2014 while the remaining seven will be upgraded this year. NRT plots of RCS, overlapped with cloud base height (CBH) are available internally to Met Office as well as externally within few hours delay (http://www.dwd.de/ceilomap). Note that some sites have both Vaisala and Jenoptik instruments while two sites are located overseas (Gibraltar and St Helena). The NRT plots are updated every 15 min. A further six stations from Ireland were added to this ceilometer network. The plots are updated each six hours (to be improved to hourly data soon)

INTRODUCTION

MET OFFICE VA NEWORK

CONCLUSIONS