STROZ Lidar Results at the MOHAVE III Campaign, October, 2009, Table Mountain, CA

During October, 2009 the GSFC STROZ Lidar participated in a campaign at the JPL Table Mountain Facility (Wrightwood, CA, 2285 m Elevation) to measure vertical profiles of water vapor from near the ground to the lower stratosphere. On eleven nights, water vapor, aerosol, temperature and ozone profiles were measured by the STROZ lidar, two other similar lidars, frost-point hygrometer sondes, and ground-based microwave instruments made measurements. Results from these measurements and an evaluation of the performance of the STROZ lidar during the campaign will be presented in this paper. The STROZ lidar was able to measure water vapor up to 13-14 km ASL during the campaign. We will present results from all the STROZ data products and comparisons with other instruments made. Implications for instrumental changes will be discussed

Correction Technique for Raman Water Vapor Lidar Signal-Dependent Bias and Suitability for Water Wapor Trend Monitoring in the Upper Troposphere

The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE (Atmospheric Laboratory for Validation, Interagency Collaboration and Education) mobile laboratory in the MOHAVE-2009 campaign. In appendices we also report on the performance of the corrected Vaisala RS92 radiosonde measurements during the campaign, on a new radiosonde based calibration algorithm that reduces the influence of atmospheric variability on the derived calibration constant, and on other results of the ALVICE deployment. The MOHAVE-2009 campaign permitted the Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated, revealing that wet biases in upper tropospheric (UT) and lower stratospheric (LS) water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the bias. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Good agreement is found between corrected ALVICE lidar measurments and those of RS92, frost point hygrometer and total column water. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most robust. The correction shown here holds promise for permitting useful upper tropospheric water vapor profiles to be consistently measured by Raman lidar within NDACC (Network for the Detection of Atmospheric Composition Change) and elsewhere, despite the prevalence of instrumental and atmospheric effects that can contaminate the very low signal to noise measurements in the UT

Stratospheric Water Vapour as Tracer for Vortex Filamentation in the Arctic Winter 2002/2003

Balloon-borne frost point hygrometers measured three high-resolution profiles of stratospheric water vapour above Ny-Ålesund, Spitsbergen during winter 2002/2003. The profiles obtained on 12 December 2002 and on 17 January 2003 provide an insight into the vertical distribution of water vapour in the core of the polar vortex.The water vapour sounding on 11 February 2003 was obtained within the vortex edge region of the lower stratosphere. Here, a significant reduction of water vapour mixing ratio was observed between 16 and 19 km. The stratospheric temperatures indicate that this dehydration was not caused by the presence of polar stratospheric clouds or earlier PSC particle sedimentation.Ozone observations on this day indicate a large scale movement of the polar vortex and show laminae in the same altitude range as the water vapour profile. The link between the observed water vapour reduction and filaments in the vortex edge region is indicated in the results of the semi-lagrangian advection model MIMOSA, which show that adjacent filaments of polar and mid latitude air can be identified above the Spitsbergen region. A vertical cross-section produced by the MIMOSA model reveals that the water vapour sonde flew through polar air in the lowest part of the stratosphere below 425 K, then passed through filaments of mid latitude air with lower water vapour concentrations, before it finally entered the polar vortex above 450 K. These results indicate that on 11 February 2003 the frost point hygrometer measured different water vapour concentrations as the sonde detected air with different origins. Instead of being linked to dehydration due to PSC particle sedimentation, the local reduction in the stratospheric water vapour profile was in this case caused by dynamical processes in the polar stratosphere

LAPBIAT Upper Troposphere Lower Stratosphere Water Vapour Validation Project: LAUTLOS - WAVVAP

LAPBIAT* Upper Troposphere Lower Stratosphere Water VapourValidation Project: LAUTLOS WAVVAPEsko Kyrö, Arctic Research Centre (FMI/ARC), Sodankylä, Finland ([email protected])Ulrich Leiterer, Meteorological Observatory Lindenberg, GermanyVladimir Yushkov, Central Aerological Observatory Moscow, RussiaRoland Neuber, Alfred Wegener Institute for Polar and Marine Research, Potsdam, GermanyPaul Ruppert, Meteolabor AG, Wetzikon, SwitzerlandAri Paukkunen, Vaisala Oyj, Helsinki, FinlandHolger Vömel, University of Colorado, Boulder, USAThe focus of this project is the improvement of water vapour measurement techniques in the Upper Troposphere and LowerStratosphere (UT/LS). Routine measurements of water vapour with high accuracy at these altitudes are an unsolved problem up tonow despite many activities in the past ten years. Water vapour is a dominant greenhouse gas in the earths atmosphere. Recentmodel calculations show that observed water vapour increases in the stratosphere contribute significantly both to surface warmingand stratospheric cooling. In addition to climate change, both direct chemical and indirect radiative effects of stratospheric waterchanges on ozone chemistry are important as well. Therefore one of the aims of the forthcoming EU COST Action 723 The Roleof the Upper Troposphere and Lower Stratosphere in Global change is to improve balloon sounding and remote sensingtechniques of water vapour measurements (see http://www.sat.uni-bremen.de/cost/). Another example of the work focusing onwater vapour is proposed by the GEWEX Water Vapour Project (GVaP) (see SPARC Report No. 2, December 2000 and thereferences therein).The idea of LAUTLOS-WAVVAP is a comparison/validation experiment, which brings together lightweight hygrometersdeveloped in different research groups, which could be used as research-type radiosondes in the UTLS region. These include:Meteolabor Snow White hygrometer, NOAA frostpoint hygrometer, CAO Flash Lyman alpha hygrometer, Lindenberg FN sonde(a modification of the Vaisala radiosonde) and the latest version of the regular Vaisala radiosonde with the humicap-polymersensor. The experimental plan is based on regular launches of multi-sensor payloads at Sodankylä in January February 2004. Theaim is to study the effect of atmospheric parameters such as ambient temperature, water vapour content or relative humidity, airpressure and solar radiation on each participating hygrometer/radiosonde records. Both night and daytime launches are planned.The campaign also aims at studying PSC occurrence and their dependence on local temperature and water vapour content. It willbe hosted by the FMI Arctic Research Centre Sodankylä assisted by Vaisala Oyj and is part of the planned Finnish contribution toCost 723 project. The campaign is partly funded from the LAPBIAT Facility, which belongs to the EU program: Access toResearch Infrastructures (see: http://www.sgo.fi/lapbiat/).* Lapland Atmosphere-Biosphere Facility Improving the Human Research Potential and the Socio-Economic knowledge Bas

A trajectory-based estimate of the tropospheric ozone column using the residual method

We estimate the tropospheric column ozone using a forward trajectory model to increase the horizontal resolution of the Aura Microwave Limb Sounder (MLS) derived stratospheric column ozone. Subtracting the MLS stratospheric column from Ozone Monitoring Instrument total column measurements gives the trajectory enhanced tropospheric ozone residual (TTOR). Because of different tropopause definitions, we validate the basic residual technique by computing the 200-hPa-to-surface column and comparing it to the same product from ozonesondes and Tropospheric Emission Spectrometer measurements. Comparisons show good agreement in the tropics and reasonable agreement at middle latitudes, but there is a persistent low bias in the TTOR that may be due to a slight high bias in MLS stratospheric column. With the improved stratospheric column resolution, we note a strong correlation of extratropical tropospheric ozone column anomalies with probable troposphere-stratosphere exchange events or folds. The folds can be identified by their colocation with strong horizontal tropopause gradients. TTOR anomalies due to folds may be mistaken for pollution events since folds often occur in the Atlantic and Pacific pollution corridors. We also compare the 200-hPa-to-surface column with Global Modeling Initiative chemical model estimates of the same quantity. While the tropical comparisons are good, we note that chemical model variations in 200-hPa-to-surface column at middle latitudes are much smaller than seen in the TTOR