d. Open access institutional repositoriesThe AMS understands there is increasing demand for institutions to provide open access to the published research being produced by employees, such as faculty, of that institution. In recognition of this, the AMS grants permission to each of its authors to deposit the definitive version of that author's published AMS journal article in the repository of the author's institution provided all of the following conditions are met: The article lists the institution hosting the repository as the author's affiliation.  The copy provided to the repository is the final published PDF of the article (not the EOR version made available by AMS prior to formal publication; see section 6).  The repository does not provide access to the article until six months after the date of publication of the definitive version by the AMS.  The repository copy includes the AMS copyright notice. T he Deep Propagating Gravity Wave Experiment (DEEPWAVE) was the first comprehensive measurement program devoted to quantifying the evolution of gravity waves (GWs) arising from sources at lower altitudes as they propagate, interact with mean and other wave motions, and ultimately dissipate from Earth's surface into the mesosphere and lower thermosphere (MLT). Research goals motivating the DEEPWAVE measurement program are summarized in Table 1. To achieve our research goals, DEEPWAVE needed to sample regions having large horizontal extents because of large horizontal GW propagation distances for some GW sources. DEEPWAVE accomplished this goal through airborne and ground-based (GB) measurements that together provided sensitivity to multiple GW sources and their propagation to, and effects at, higher altitudes. DEEPWAVE was performed over and around the GW "hotspot" region of New Zealand (Fig.1, top) during austral winter, when strong vortex edge westerlies provide a stable environment for deep GW propagation into the MLT.DEEPWAVE airborne measurements employed two research aircraft during a core 6-week airborne field program based at Christchurch, New Zealand, from 6 June to 21 July 2014. The National Science 425MARCH 2016 AMERICAN METEOROLOGICAL SOCIETY | Foundation (NSF)/National Center for Atmospheric Research (NCAR) Gulfstream V (GV) provided in situ, dropsonde, and microwave temperature profiler (MTP) measurements extending from Earth's surface to ~20 km throughout the core field program (see Table 2). The GV also carried three new instruments designed specifically to address DEEPWAVE science goals: 1) a Rayleigh lidar measuring densities and temperatures from ~20 to 60 km, 2) a sodium resonance lidar measuring sodium densities and temperatures from ~75 to 100 km, and 3) an advanced mesosphere temperature mapper (AMTM) measuring temperatures in a horizontal plane at ~87 km with a field of view (FOV) of ~120 km along track and 80 km cross track. AMTM measurements were augmented by two side-viewing infrared (IR) airglow "wing" cameras also viewing an ~87-km altitude that extended the cross-track FOV to ...

[1] Tropical deep convection and its dynamical effect on the tropopause and stratosphere are investigated using a suite of data from the Upper Atmospheric Research Satellite (UARS) Microwave Limb Sounder (MLS), including upper tropospheric humidity, cloud radiance, and gravity wave measurements. For this purpose, geographical distributions of temperature, water vapor, and cloudiness in the tropical tropopause layer (TTL) are compared with corresponding maps of gravity wave variance in the stratosphere. In addition, ECMWF global wind divergent and velocity potential fields as well as NOAA outgoing longwave radiation and CMAP rainfall data are analyzed to help pinpoint the locations of deep convection. We found that high-altitude clouds near the bottom of TTL ($147 hPa) are usually surrounded by high-humidity air, and their spatial pattern and seasonal variability are closely associated with regions of vigorous summertime deep convection. Upward propagating gravity waves generated from these convection regions are shifted poleward by prevailing stratospheric winds. We estimate that tropical deep convection lifts $5% of the cloud tops to altitudes above 100 hPa and that most of the extreme deep convection events occur in the Western Pacific and Indian monsoon regions. Lowtemperature regions in the TTL are associated with, but often drift away from, the center of deep convection. Regions of water vapor maxima near the bottom of TTL are located directly above the deep convection centers, but this moisture behavior is somewhat reversed at the top of the TTL. The integrated picture derived from this study implies that convective scale motions could be important in affecting short-term dehydration processes in the TTL. Our results also suggest that the spatial organization and temporal development of tropical convective systems will be better monitored with the follow-on Earth Observing System (EOS) Aura satellite instruments and lead to improved understanding of the complex interaction of tropical convection with largescale dynamic and thermodynamic conditions.

Abstract. Space borne infrared limb emission measurements by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) reveal the formation of a belt of polar stratospheric clouds (PSCs) of nitric acid trihydrate (NAT) particles over Antarctica in mid-June 2003. By mesoscale microphysical simulations we show that this sudden onset of NAT PSCs was caused by heterogeneous nucleation on ice in the cooling phases of large-amplitude stratospheric mountain waves over the Antarctic Peninsula and the Ellsworth Mountains. MIPAS observations of PSCs before this event show no indication for the presence of NAT clouds with volume densities larger than about 0.3 µm3/cm3 and radii smaller than 3 µm, but are consistent with supercooled droplets of ternary H2SO4/HNO3/H2O solution (STS). Simulations indicate that homogeneous surface nucleation rates have to be reduced by three orders of magnitude to comply with the observations.

[1] Despite evidence from ground-based data that flow over mountains is a dominant source of gravity waves (GWs) for the Northern Hemisphere winter middle atmosphere, GW-related signals in global limb radiances from the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) have shown little direct evidence of mountain waves. We address this issue by combining a renewed analysis of MLS limb-track and limb-scan radiances with global mountain wave modeling using the Naval Research Laboratory Mountain Wave Forecast Model (MWFM). MLS radiance variances show characteristics consistent with mountain waves, such as enhanced variance over specific mountain ranges and annual variations that peak strongly in winter. However, direct comparisons of MLS variance maps with MWFM-simulated mountain wave climatologies reveal limited agreement. We further develop a detailed ''MLS GW visibility function'' that accurately specifies the three-dimensional in-orbit sensitivity of the MLS limb-track radiance measurement to a spectrum of GWs with different wavelengths and horizontal propagation directions. On postprocessing MWFM-generated mountain wave fields through these MLS visibility filters, we generate MWFM variance maps that agree substantially better with MLS radiance variances. This combined data analysis and MLSfiltered MWFM modeling leads us to conclude that many MLS variance enhancements can be associated with mountain waves forced by flow over specific mountainous terrain. These include mountain ranges in Europe (e.g., Scandinavia; Alps; Scotland; Ural, Putoran, Altai, Hangay and Sayan Mountains; Yablonovyy, Stanovoy, Khingan, Verkhoyansk and Central Ranges), North America (e.g., Brooks Range, MacKenzie Mountains, Colorado Rockies), southeastern Greenland, and Iceland. Our results show that given careful consideration of the in-orbit sensitivity of the instrument to GWs, middle atmospheric limb radiances measured from UARS MLS, as well as from the new MLS instrument on the Earth Observing System (EOS) satellite, can provide important global information on mountain waves in the extratropical Northern Hemisphere stratosphere and mesosphere.

[1] We show high-resolution satellite observations of mountain wave events in the stratosphere above South Georgia Island in the remote southern Atlantic Ocean and compute the wave momentum fluxes for these events. The fluxes are large, and they imply important drag forces on the circulation. Small island orography is generally neglected in mountain wave parameterizations used in global climate models because limited model resolution treats the grid cell containing the island as ocean rather than land. Our results show that satellite observations can be used to quantitatively constrain mountain wave momentum fluxes, and they suggest that mountain waves from island topography may be an important missing source of drag on the atmospheric circulation.