Co-Chairs: Kohei Mizutani, Xinzhao Chu, Scott Spuler, Anne Garnier S9O-01 - Invited Talk
TEMPERATURE TRENDS IN THE MIDDLE ATMOSPHERE AND THE ROLE OF THE DYNAMICS
Philippe Keckhut1, Guillaume Angot1, Alain Hauchecorne1, Beatrix Funatsu1, Chantal Claud2
1LATMOS-IPSL, Université de Versailles Saint-Quentin, 11, Boulevard d'Alembert, 78280 Guyancourt, France
2LMD-IPSL, Ecole Polytechnique, 91128 Palaiseau Cedex, France
The continuous temperature measurements since 1979 using Rayleigh scattering have been used to derive the variability, long-term trends and to insure satellite adjustment. Some discrepancies remain due to tides, under-sampling, and dynamic feedbacks. A new analysis method has been developed based on background temperatures instead of mean temperatures. The winter trend estimates was smaller than summer estimates before and is in better agreement with the new method. Stratospheric warmings play a critical role in trend estimates. Sudden stratospheric warmings seem to be associated with a cooling at ground level.
S9O-02
ARCTIC VERSUS MIDLATITUDE ICE CLOUDS: DIFFERENCES REVEALED BY GROUND-BASED LIDAR AND CALIPSO PROBING
Kenneth Sassen, Vinay K. Kayetha
Geophysical Institute University of Alaska Fairbanks, USA
The view of clouds provided by the CALIPSO lidar is highlighting new concerns about the basic natures of clouds on a global scale. Previously, our knowledge of clouds was dominated by midlatitude research, but it is becoming clear from the global CALIPSO dataset that the distribution and physical properties of various cloud types is strongly a function of latitude and geography. Currently under examination are the differences between high (i.e., cirrus) and midlevel (altostratus) ice clouds based on multi-year polarization lidar measurement programs from FARS in Salt lake City, Utah, and AFARS (the Arctic Facility for Atmospheric Remote Sensing) in Fairbanks, Alaska. Although the average monthly cloud base and top temperatures of cirrus (defined as cloud top temperatures < -40 °C and optical depths <
~3.0 based on FARS research) are similar, the heights, pressures, and wind speeds/directions are in poor agreement. Of course, these discrepancies are a reflection of differences in tropopause heights (normally about 2-km lower at AFARS), and the weather patterns locally responsible for cirrus generation. A primary cause of the latter is the comparative lack of Arctic jet stream systems for much of the year, versus midlatitudes. Major differences are also indicated in the frequency and properties of midlevel altostratus ice clouds, which at high latitudes often are optically thin or even subvisual particularly during the winter season. Another fundamental difference appears to be the mesoscale organization of ice clouds in the Arctic as revealed by CALIPSO data, versus the synoptic-scale organizations at midlatitudes. We will provide and compare ice cloud climatologies from FARS and AFARS and discuss the implications for the improved global characterization of ice clouds, including those of the tropics from earlier CALIPSO research.
LONG-TERM LIDAR MEASUREMENTS AT TABLE MOUNTAIN, CA, AND MAUNA LOA, HI, FOR THE NETWORK FOR THE DETECTION OF ATMOSPHERIC COMPOSITION
CHANGE (NDACC)
Stuart McDermid, Thierry Leblanc, Guillaume Kirgis, Daniel Walsh
Jet Propulsion Laboratory, California Institute of Technology, Table Mountain Facility, P.O. Box 367, Wrightwood, CA 92397, USA
For many years, beginning in 1988, the JPL Atmospheric Lidar Group has operated a number of lidar systems at the Table Mountain Facility (TMF), California (34.4°N, 117.7°W, elevation 2300 m) and at Mauna Loa Observatory (MLO), Hawaii (19.5°N, 155.5°W, elevation 3400 m). These include systems for measurements of tropospheric and stratospheric ozone, tropospheric and stratospheric aerosols, stratospheric and mesospheric temperature, and tropospheric-lower stratospheric water vapor. Also, recently we are involved to try an extend some of these measurements down to the Earth surface. These lidar systems are operated on a continuous and long-term basis under the framework of the Network for the Detection of Atmospheric Composition Change (NDACC) and have acquired many thousands of profiles. This talk will review some of the lidar development and long-term results derived from the extensive database of observations at TMF and MLO.
S9O-04
POSSIBLE LINKAGE BETWEEN TROPOSPHERIC AND POLAR STRATOSPHERIC CLOUDS OBSERVED BY SPACE-BORNE LIDAR IN THE ARCTIC?
Peggy Achtert, M. Karlsson Andersson, Farahnaz Khosrawi and Jörg Gumbel Department of Meteorology, Stockholm University, Stockholm, Sweden
Measurements performed with the lidar aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite were used to investigate a possible connection between the occurrence of Arctic Polar Stratospheric Clouds (PSCs) and tropospheric clouds. PSCs observed by CALIPSO during the Arctic winter 2007/08 were classified according to their type (STS, NAT, or ice) and to the kind of underlying tropospheric clouds. 172 out of 211 observed PSCs occurred in connection with tropospheric clouds. 72% of these 172 PSCs were observed above deep-tropospheric clouds. Thus, the type of a PSC seems to be connected to the characteristics of the underlying tropospheric clouds. During the Arctic winter 2007/08 PSCs consisting of ice were mainly observed in connection with deep-tropospheric cloud systems while other PSCs than ice was detected above cirrus. No correlation was found between PSC occurrence and the top temperature of tropospheric clouds. This finding suggest that Arctic PSC formation is connected to adiabatic rather than radiative cooling.
S9O-05
LIDAR MEASUREMENTS OF ARCTIC BOUNDARY LAYER OZONE DEPLETION EVENTS OVER THE FROZEN ARCTIC OCEAN
Jeffery A Seabrook1, Jim Whiteway1, Leonce Komguem1, Ralf Staebler2 and Jan Bottenheim2
1York University, Centre for Research in Earth and Space Science, 416 Petrie Science And Engineering Building, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
2Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada
A differential absorption light detection and ranging instrument (Differential Absorption Lidar or DIAL) was installed on-board the Canadian Coast Guard Ship Amundsen and operated during the winter and spring of 2008. During this period the vessel was stationed in the Amundsen Gulf (71◦N, 121-124◦W), approximately 10-40 km off the south coast of Banks Island. The LIDAR was operated to obtain a continuous record of the vertical profile of ozone concentration in the lower atmosphere (60 -1000 m) over the sea ice during the polar sunrise. The observations included several ozone depletion events (ODEs) within the atmospheric boundary layer. The strongest ODEs consisted of air with ozone mixing ratio less than 10 ppbv up to heights varying from 200 m to 600 m, and the increase to the background mixing ratio of about 35-40 ppbv occurred within about 200 m in the overlying air. All of the observed ODEs were connected to the ice surface. Back trajectory calculations indicated that the ODEs only occurred in air that had spent an extended period of time below a height of 500 m above the sea ice. Also, all the ODEs occurred in air with temperature below -25◦C. Air not depleted in ozone was found to be associated with warmer air originating from above the surface layer.
S9O-06
SIMULTANEOUS MEASUREMENTS OF FREE TROPOSPHERIC WATER VAPOR AND OZONE
Hannes Vogelmann and Thomas Trickl
Karlsruhe Institute of Technology, IMK-IFU, Garmisch-Partenkirchen, Germany
We report on simultaneous free-tropospheric profiling of ozone and water vapor with DIAL at Garmisch-Partenkirchen (Germany) and the nearby Mt. Zugspitze (at 2675 m a.s.l.) within a program of ground-based routine measurements started in 2007. Additionally, backscatter from aerosols is recorded as byproduct by both systems. Gathering these three parameters allows us to create finger prints for the probed air and yields new possibilities for characterizing and quantifying atmospheric dynamics and atmospheric long range transport. We present some exciting examples, related to processes such as stratospheric intrusions, Saharan dust outbreaks and trans-Atlantic long range transport. Our results illustrate the value of synergistic combination of coincidently measured different atmospheric components regarded as tracers for large-scale atmospheric dynamics.
DEVELOPMENT AND APPLICATION OF AN AIRBORNE DIFFERENTIAL ABSORPTION LIDAR FOR THE SIMULTANEOUS MEASUREMENT OF OZONE AND WATER VAPOR IN
THE TROPOPAUSE REGION
Felix Steinebach, Andreas Fix, Martin Wirth, Gerhard Ehret
Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Physik der Atmosphäre, D-82234 Oberpfaffenhofen, Germany
A new, combined, lidar system has been developed that is able to simultaneously measure profiles of ozone and water vapor onboard of a comparatively small aircraft. The concurrent measurement of these complementary trace species in the upper troposphere and lower stratosphere allows inferring exchange processes in the tropopause region. Whereas an advanced H2O differential absorption lidar at 935 nm has successfully been developed and extensively tested at DLR in the past, we concentrate here on amending this lidar by addition of a UV channel to measure ozone. The transmitter of the ozone DIAL is based on a near-IR optical parametric oscillator that is frequency-converted into the UV spectral range by intracavity sum frequency mixing. Hereby, a continuous UV tuning range of ~ 302-316 nm has been achieved. The average output power in this range is higher than 1 W corresponding to more than 10 mJ per pulse at a repetition rate of 100 Hz. While airborne measurements are still pending, ground-based validation using both ozone sondes and ozone DIAL has successfully been performed and demonstrates the potential of this system.
S9O-08
CHARACTERIZING POLLUTION TRANSPORT IN SOUTHERN CALIFORNIA USING AIRBORNE LIDAR MEASUREMENTS OF OZONE AND WIND PROFILES Christoph J. Senff1,2, Raul J. Alvarez II2, W. Alan Brewer2, R. Michael Hardesty2, Andrew O.
Langford2, Robert M. Banta2, Fay Davies3, Guy N. Pearson4, Scott P. Sandberg2, Richard D.
Marchbanks1,2, Ann M. Weickmann1,2
1CIRES, University of Colorado, 216 UCB, Boulder, CO 80309, USA
2NOAA/ESRL, 325 Broadway, Boulder CO 80305, USA
3University of Leeds, Leeds, LS2 9JT, UK
4HALO Photonics, Leigh, Worcester, WR6 5LA, UK
During the CalNex experiment from May through July 2010, we co-deployed NOAA’s TOPAZ ozone and aerosol lidar with the University of Leeds Doppler wind lidar on a Twin Otter aircraft. The Leeds Doppler lidar is a compact, low pulse energy, high repetition rate, commercially-available instrument. For the CalNex study, we paired the Doppler lidar with a custom-built optical wedge scanner, which enabled measurements of full 3-dimensional wind profiles beneath the aircraft. The combination of the highly resolved airborne ozone and wind lidar measurements provided an unprecedented look at pollution transport mechanisms in California. Here, we use the collocated lidar observations to characterize important ozone transport processes between the greater Los Angeles area and adjacent air basins in southern California. The mountainous terrain surrounding the Los Angeles Basin and the proximity to the Pacific Ocean give rise to a number of local, often complex, flow patterns, including the land-sea breeze circulation, mountain gap flows, and lifting and venting processes along mountain slopes. Our combined airborne ozone and wind lidar observations are ideally suited to assess the role of these flow patterns in redistributing ozone in southern California and to estimate the magnitude of the ozone flux associated with these various transport processes.
S9O-09
LONG-TERM OBSERVATIONS OF THE NABRO STRATOSPHERIC AEROSOL LAYER OVER ÉVORA, PORTUGAL
Wagner, Frank1, Jana Preißler1, Sérgio Pereira1 and Juan Luis Guerrero Rascado1,2,3
1Centro de Geofísica, Universidade de Évora, Rua Romão Ramalho 59, 7000-671 Évora, Portugal
2Andalusian Center for Environmental Research (CEAMA), University of Granada – Autonomous Government of Andalusia, Av. del Mediterráneo s/n, 18006, Granada, Spain
3Department of Applied Physics, University of Granada, Fuentenueva s/n, 18071, Granada, Spain
Stratospheric aerosol particles, most likely caused by the eruption of the Nabro volcano, Eritrea, have been detected in Évora, Portugal since the end of June 2011. The aerosol plume could be observed over more than 8 months until February 2012. Its development in terms of vertical and temporal distribution was studied and is presented here. The layer was detected between 16 and 18 km above sea level (asl) in June 2011. Eight months later, in February 2012, the layer stretched between 9 and 20 km asl. The aerosol optical depth at 532 nm was estimated to be 0.048.
S9O-10
STATISTICAL CHARACTERISTICS OF ATMOSPHERIC GRAVITY WAVE IN THE MESOPAUSE REGION OBSERVED WITH A SODIUM LIDAR AT BEIJING, CHINA
Guotao Yang, Shaohua Gong, JihongWang, Jiyao Xu, Sai Guan, Xiaoxi Zhang
State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, 100190, China
Nightly and seasonal variations of atmospheric gravitywave (AGW) activity in the sodium layer are investigated by analyzing 253 nights of sodium lidar observations.These observations were made from April 2010 to September 2011 at Yanqing, Beijing (40.3°N, 116.2°E). Vertical wavelengths, periods and phase velocities of 147 quasi-monochromatic AGWs are extracted from the lidar data. An average parameter relationship λz=0.247T0.509 is found. Statistical results show that the activity of AGW usually has two maxima per night, and monthly results show that it has a maximum in summer and a minimum in winter. Convection and topography of Qinghai-Tibet Plateau are regarded as the main sources of these AGWs. Influences of seasonally varying temperature and background winds on AGW activity are discussed.
MCMURDO LIDAR CAMPAIGN: A NEW LOOK INTO POLAR UPPER ATMOSPHERE Xinzhao Chu1, Zhibin Yu1, Cao Chen1, Weichun Fong1, Wentao Huang1, Chester S. Gardner2,
Zhangjun Wang1,3, Brendan Roberts1 and John A. Smith1
1University of Colorado at Boulder, 216 UCB, CIRES, Boulder, CO 80309, USA
2University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
3Shandong Academy of Sciences, Qingdao, Shandong, China
A new lidar campaign is ongoing at McMurdo (77.8°S, 166.7°E), Antarctica with a Fe Boltzmann lidar since December 2010. The data have extended resonance fluorescence lidar measurements into the thermosphere up to 155 km, leading to several intriguing science discoveries in the polar upper atmosphere. This is the first ever lidar detection of neutral species deep into the thermosphere, providing a new look in the thermosphere composition, temperature and dynamics. Furthermore, the large temperature coverage from 30 to 150 km of the lidar allows us to trace gravity waves from 30 to 150 km, providing crucial information to wave coupling and dynamics at this wave “hot spot”. The high-resolution lidar data reveal rich spectra of gravity waves. The full diurnal coverage of the lidar enables us to characterize mesospheric clouds and many summer phenomena, leading to a better understanding of polar space science.