Abstract. The VAMOS 1 Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) was an international field program designed to make observations of poorly understood but critical components of the coupled climate system of the southeast Pacific. This region is characterized by strong coastal upwelling, the coolest SSTs in the tropi- cal belt, and is home to the largest subtropical stratocumulus deck on Earth. The field intensive phase of VOCALSREx took place during October and November 2008 and constitutes a critical part of a broader CLIVAR program (VOCALS) designed to develop and promote scientific activities leading to improved understanding, model simulations, and predictions of the southeastern Pacific (SEP) coupled ocean-atmosphere-land system, on diurnal to interannual timescales. The other major components of VOCALS are a modeling program with a model hierarchy ranging from the local to global scales, and a suite of extended observations from regular research cruises, instrumented moorings, Published by Copernicus Publications on behalf of the European Geosciences Union. R. Wood et al.: VOCALS operationsand satellites. The two central themes of VOCALS-REx focus upon (a) links between aerosols, clouds and precipitation and their impacts on marine stratocumulus radiative properties, and (b) physical and chemical couplings between the upper ocean and the lower atmosphere, including the role that mesoscale ocean eddies play. A set of hypotheses designed to be tested with the combined field, monitoring and modeling work in VOCALS is presented here. A further goal of VOCALS-REx is to provide datasets for the evaluation and improvement of large-scale numerical models. VOCALSREx involved five research aircraft, two ships and two surface sites in northern Chile. We describe the instrument payloads and key mission strategies for these platforms and give a summary of the missions conducted.
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 ...
The upper-air sounding network for Dynamics of the Madden-Julian Oscillation (DYNAMO) has provided an unprecedented set of observations for studying the MJO over the Indian Ocean, where coupling of this oscillation with deep convection first occurs. With 72 rawinsonde sites and dropsonde data from 13 aircraft missions, the sounding network covers the tropics from eastern Africa to the western Pacific. In total nearly 26 000 soundings were collected from this network during the experiment's 6-month extended observing period (from October 2011 to March 2012). Slightly more than half of the soundings, collected from 33 sites, are at high vertical resolution. Rigorous post-field phase processing of the sonde data included several levels of quality checks and a variety of corrections that address a number of issues (e.g., daytime dry bias, baseline surface data errors, ship deck heating effects, and artificial dry spikes in slow-ascent soundings).Because of the importance of an accurate description of the moisture field in meeting the scientific goals of the experiment, particular attention is given to humidity correction and its validation. The humidity corrections, though small relative to some previous field campaigns, produced high-fidelity moisture analyses in which sonde precipitable water compared well with independent estimates. An assessment of operational model moisture analyses using corrected sonde data shows an overall good agreement with the exception at upper levels, where model moisture and clouds are more abundant than the sonde data would indicate.
This paper briefly presents the West African Monsoon (WAM) Modeling and Evaluation Project (WAMME) and evaluates WAMME general circulation models' (GCM) performances in simulating variability of WAM precipitation, surface temperature, and major circulation features at seasonal and intraseasonal scales in the first WAMME experiment. The analyses indicate that models with specified sea surface temperature generally have reasonable simulations of the pattern of spatial distribution of WAM seasonal mean precipitation and surface temperature as well as the averaged zonal wind in latitudeheight cross-section and low level circulation. But there are large differences among models in simulating spatial correlation, intensity, and variance of precipitation compared with observations. Furthermore, the majority of models fail 123Clim Dyn (2010) 35:3-27 DOI 10.1007 to produce proper intensities of the African Easterly Jet (AEJ) and the tropical easterly jet. AMMA Land Surface Model Intercomparison Project (ALMIP) data are used to analyze the association between simulated surface processes and the WAM and to investigate the WAM mechanism. It has been identified that the spatial distributions of surface sensible heat flux, surface temperature, and moisture convergence are closely associated with the simulated spatial distribution of precipitation; while surface latent heat flux is closely associated with the AEJ and contributes to divergence in AEJ simulation. Common empirical orthogonal functions (CEOF) analysis is applied to characterize the WAM precipitation evolution and has identified a major WAM precipitation mode and two temperature modes (Sahara mode and Sahel mode). Results indicate that the WAMME models produce reasonable temporal evolutions of major CEOF modes but have deficiencies/ uncertainties in producing variances explained by major modes. Furthermore, the CEOF analysis shows that WAM precipitation evolution is closely related to the enhanced Sahara mode and the weakened Sahel mode, supporting the evidence revealed in the analysis using ALMIP data. An analysis of variability of CEOF modes suggests that the Sahara mode leads the WAM evolution, and divergence in simulating this mode contributes to discrepancies in the precipitation simulation.
''close'' budgets since too many fundamental processes are missing. Models that properly represent the many complicated atmospheric and near-surface interactions are also required. This preliminary synthesis therefore included a representative global general circulation model, regional climate model, and a macroscale hydrologic model as well as a global reanalysis and a regional analysis. By the qualitative agreement among the models and available observations, it did appear that we now qualitatively understand water and energy budgets of the Mississippi River Basin. However, there is still much quantitative uncertainty. In that regard, there did appear to be a clear advantage to using a regional analysis over a global analysis or a regional simulation over a global simulation to describe the Mississippi River Basin water and energy budgets. There also appeared to be some advantage to using a macroscale hydrologic model for at least the surface water budgets.
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