Measurement and modeling of moist processes

The keynote talk summarized five years of work simulating observed mesoscale convective systems with the RAMS (Regional Atmospheric Modeling System) model. Excellent results are obtained when simulating squall line or other convective systems that are strongly forced by fronts or other lifting mechanisms. Less highly forced systems are difficult to model. The next topic in this colloquium was measurement of water vapor and other constituents of the hydrologic cycle. Impressive accuracy was shown measuring water vapor with both the airborne DIAL (Differential Absorption Lidar) system and the the ground-based Raman Lidar. NMC's plans for initializing land water hydrology in mesoscale models was presented before water vapor measurement concepts for GCIP were discussed. The subject of using satellite data to provide mesoscale moisture and wind analyses was next. Recent activities in modeling of moist processes in mesoscale systems was reported on. These modeling activities at the Canadian Atmospheric Environment Service (AES) used a hydrostatic, variable-resolution grid model. Next the spatial resolution effects of moisture budgets was discussed; in particular, the effects of temporal resolution on heat and moisture budgets for cumulus parameterization. The conclusion of this colloquium was on modeling scale interaction processes

A Case Study of Processes Impacting Precipitation Phase and Intensity during the Vancouver 2010 Winter Olympics

Accurate forecasting of precipitation phase and intensity was critical information for many of the Olympic venue managers during the Vancouver 2010 Olympic and Paralympic Winter Games. Precipitation forecasting was complicated because of the complex terrain and warm coastal weather conditions in the Whistler area of British Columbia, Canada. The goal of this study is to analyze the processes impacting precipitation phase and intensity during a winter weather storm associated with rain and snow over complex terrain. The storm occurred during the second day of the Olympics when the downhill ski event was scheduled. At 0000 UTC 14 February, 2 h after the onset of precipitation, a rapid cooling was observed at the surface instrumentation sites. Precipitation was reported for 8 h, which coincided with the creation of a nearly 0°C isothermal layer, as well as a shift of the valley flow from up valley to down valley. Widespread snow was reported on Whistler Mountain with periods of rain at the mountain base despite the expectation derived from synoptic-scale models (15-km grid spacing) that the strong warm advection would maintain temperatures above freezing. Various model predictions are compared with observations, and the processes influencing the temperature, wind, and precipitation types are discussed. Overall, this case study provided a well-observed scenario of winter storms associated with rain and snow over complex terrain

On the effects of cumulus convection on mid-latitude explosive cyclones

The effects of cumulus cloud ensembles on the dynamics of mid-latitude explosive cyclones are studied both from a diagnostic and from a theoretical point of view.A diagnostic study of an explosive winter storm shows that significant residuals attributable to cumulus convection are present in the horizontal momentum, thermodynamic and vorticity budgets, but not in the divergence budget, and that the finite-amplitude wave is well described by linear dynamics.A scale analysis appropriate for mid-latitude synoptic-scale waves with intense convection indicates the importance of three mechanisms by which cumulus clouds can influence these storms. These mechanisms are the thermodynamic and dynamical effects of clouds, and certain cloud-induced non-geostrophic effects.A series of experiments with linear models of moist baroclinic instability using an idealized basic state shows the significant role of the ageostrophic terms and the important damping due to the dynamical effects of clouds. With a realistic wintertime basic state, we conclude that the different cloud forcings are necessary to account for the observed features of explosive storms

Modeling the Surface Energy Budget during the Thawing Period of the 2006 Montreal Urban Snow Experiment

International audienceThe Montreal Urban Snow Experiment was dedicated to furthering the understanding of micrometeoro-logical processes involved in the late winter-early spring transition period in a Canadian city. A surface energy budget (SEB) measurement site was installed in a dense residential area of Montreal for several weeks in 2005 and 2006. This paper focuses on the last 6 days of the 2006 experiment (23-28 March 2006), after snowmelt and before vegetation became active, with the objectives of providing a better understanding of physical processes involved during this transition period and examining their impact on the SEB. The Town Energy Balance urban canopy model and the Interactions between Soil, Biosphere, and Atmosphere force-restore land surface model are used in stand-alone mode and are forced with meteorological data measured at the top of a 20-m AGL instrumented tower. Preliminary results reveal deficiencies in the models' ability to simulate the surface energy budget partitioning, and in particular show overestimation of the sensible heat flux. Sensitivity studies indicate that a large portion of these problems is related to the latent heat transfer involved in natural soil freeze/thaw processes, which has a significant effect on the surface energy budget in this urban area. It is also found that the SEB in this particular situation is very sensitive to the thermal roughness length used for local energy exchange over the roof and road surfaces

A web-based tailored nursing intervention to support illness management in patients hospitalized for an acute coronary syndrome : a pilot study

Background: Illness management after an acute coronary syndrome (ACS) is crucial to prevent cardiac complications, to foster participation in a cardiac rehabilitation (CR) program, and to optimize recovery. Web-based tailored interventions have the potential to provide individualized information and counseling to optimize patient’s illness management after hospital discharge. Objective: We aimed to assess the feasibility and acceptability of a Web-based tailored intervention (TAVIE@COEUR) designed to improve illness management in patients hospitalized for an ACS. Illness management outcomes were operationalized by self-care, medication adherence, anxiety management, cardiac risk factors reduction, and enrollment in a CR program. Methods: This posttest pilot study was conducted with one group (N=30) of patients hospitalized for an ACS on the coronary care unit of a tertiary cardiology center. TAVIE@COEUR comprises three Web-based sessions, with a duration ranging from 10 to 45 min and is structured around an algorithm to allow the tailoring of the intervention to different pathways according to patients’ responses to questions. TAVIE@COEUR includes 90 pages, 85 videos, and 47 PDF documents divided across session 1 (S1), session 2 (S2), and session 3 (S3). These sessions concern self-care and self-observation skills related to medication-taking (S1), emotional control and problem-solving skills (S2), and social skills and interacting with health professionals (S3). Throughout the videos, a virtual nurse (providing the intervention virtually) guides the participants in the acquisition of self-care skills. Patients completed S1 of TAVIE@COEUR before hospital discharge and were asked to complete S2 and S3 within 2 weeks after discharge. Feasibility indicators were extracted from the TAVIE@COEUR system. Data regarding acceptability (satisfaction and appreciation of the platform) and preliminary effect (self-care, medication adherence, anxiety management, risk factor reduction, and CR enrollment) were assessed through questionnaires at 1 month following discharge. Preliminary effect was assessed by comparing baseline and 1-month illness management variables. Results: Of the 30 participants, 20 completed S1, 10 completed S2, and 5 completed S3. Good acceptability scores were observed for ease of navigation (mean=3.58, standard deviation [SD]=0.70; scale=0-4), ease of understanding (mean=3.46, SD=0.63; scale=0-4), and applicability (mean=3.55, SD=0.74; scale=0-4). The lowest acceptability scores were observed for information tailoring (mean=2.93, SD=0.68; scale=0-4) and individual relevance (mean=2.56, SD=0.96; scale=0-4). With regard to preliminary effect, we observed an overall self-care at 1 month following discharge score higher than at baseline (mean at 1 month=54.07, SD=3.99 vs mean at baseline=49.09, SD=6.92; scale-0-60). Conclusions: Although participants reported general satisfaction and appreciation of TAVIE@COEUR, acceptability and feasibility results show the need for further development of the Web-based intervention to enhance its tailoring before undertaking a full-fledged randomized controlled trial. This may be accomplished by optimizing the adaptability of TAVIE@COEUR to patients’ knowledge, needs, interests, individual capabilities, and emotional and cognitive responses during session completion