Mission & Vision
The mission of the Mesoscale and Microscale Meteorology Laboratory is to advance the understanding of the meso- and microscale aspects of weather and climate, and to apply this knowledge to benefit society.
Since its inception over 27 years ago, the Mesoscale and Microscale Meteorology Laboratory (MMM) has excelled in fundamental research covering the dynamics and physics of mesoscale (1 – 1000 km) and microscale (106 – 1000m) atmospheric flows and processes. This work continues, but through time increasing emphasis has been placed on the modeling and prediction of these phenomena. MMM builds upon and leverages collaborations within NCAR and throughout the community to achieve more accurate mesoscale weather forecasts and climate prediction and projections.
The principal tool for atmospheric prediction is the numerical weather prediction (NWP) model. The accuracy of the NWP model depends on the discrete representation of the continuous equations believed to be governing atmospheric motion, the representation of unresolved small-scale motions (e.g., boundary-layer turbulence and cloud microphysics) that have important effects on the resolved larger-scale motion, and the data-ingest systems used for model initialization and forecast verification. Thus to advance the science of atmospheric prediction, MMM has endeavored to produce the most accurate and computationally efficient numerical models, more effective systems of data assimilation, and better representations of processes not currently resolved in present-day NWP models. The result of our efforts, with extensive external contributions, is the WRF model, now serving a global community.
As advanced as WRF is, demand for forecast accuracy continues to be ahead of supply. For example, there is a growing demand for mesoscale predictions on climatic time scales. This demand has been the motivation behind the extensive NRCM simulation research and the growth of a hybrid statistical-dynamical prediction approach. It is also one of the forces behind the recent development of MPAS, with a priority objective to bridge the weather and climate divide and enable predictions of regional climate and high-impact weather statistics on decadal time scales. This regional-climate focus will leverage development efforts from both the climate-prediction and weather-prediction communities, and promote a wide range of collaborative activities with academic, government, industry, societal, and local government groups. Recognizing that prediction is interpreted by users within their own frameworks of risk perception and action, MMM strives to adapt our research and our predictions in ways that improve the usability of use of weather and climate information. Over the last five years, MMM has built a core interdisciplinary program with expertise in communication and use of weather-related information.
The improvement of NCAR community models depends critically on the feedback from forecasters and climate-model users. MMM has led the way with WRF for the first experimental real-time high-resolution (4km grid size in 2003) forecasts over the continental U.S. in summer (when convection poses a particularly significant challenge to any forecast model) and the recent NRCM climate simulation also at 4km resolution. These efforts continue today at higher resolution and over larger domains, experimenting with new data-assimilation strategies and forecast-verification techniques. They go hand-in-hand with field experiments (e.g., MPEX planned for 2013) providing high-resolution data sets that help check on the fidelity of the model forecasts. Since 2004, MMM has also led the way with experimental real-time high-resolution forecasts of tropical cyclones. Again, field programs (e.g., PREDICT, GRIP, 2010) and new data-assimilation strategies have been critical components of the forecast-system development.
The small-scale meteorological processes that most affect the accuracy of weather and climate predictions are: the physics of clouds and precipitation, the effects of turbulence and surface exchange, and how these processes act in combination. Hence MMM has continued to place emphasis on boundary-layer and cloud-microphysics research. For example, the importance of air-sea interaction and water and ice latent heating on tropical cyclones has been appreciated for decades, but due to the extreme conditions at the sea surface and in clouds, only recently has progress been made both through observations and advanced numerical simulations. MMM scientists have played leading roles in this research and have partnered with university colleagues, other NCAR laboratories, and outside agencies to address these issues and to meet new demands for boundary-layer information coming from the renewable-energy industry.
The ability to predict cloud effects continues to be a weak link in weather and climate models. The effects of clouds run the gamut from the NWP problem of the timing, location, amount and type of precipitation expected, to the climate problem in which the distribution and nature of clouds play a critical role in future-climate projections, to evaluation of active remote sensing (lidar, radar) from spaceborne instruments (CloudSat, CALIPSO). For these reasons, MMM continues a robust research effort on the microphysics of clouds, including the effects of aerosols, ice nuclei (ICE-T), and dust.
In summary the fundamental research conducted in MMM is essential to weather- and climate-model development both in the improvement of current models and for providing the necessary groundwork for future models. Based on extensive consultation with staff and the community at large, the following pages describe recent progress and future plans for advancement in these areas.