PRESTO: PREcipitation STructures over Orography.
Lead Research Organisation:
University of Manchester
Department Name: Earth Atmospheric and Env Sciences
Abstract
Flash floods cause loss of life and billions of pounds of damage each year within the UK, and take an additional toll on society through lasting impacts including a four-fold enhancement in the risk of depression. Because of the acute hazards and long-term consequences of these events, it is essential that they be accurately understood and predicted. Two of the three principal mechanisms behind UK flash-flooding events are convective storms and orographic precipitation (the other being frontal systems). Their impact has been reinforced in recent years by a series of devastating events. The Boscastle flood of 2004 and the Ottery St Mary's hailstorm of 2008 were both caused by quasi-stationary convective storms, and the Carlisle flood of 2005 and Cockermouth flood of 2009 were both caused by orographically enhanced rainfall. Although convection and orography may act independently to produce extreme rainfall, they are often closely linked over the complex UK terrain. The mechanical ascent upstream, over, and downwind of steep terrain and the thermally-driven ascent due to elevated heating are primary convection-initiation mechanisms in conditionally unstable flows. Because orography is fixed in space, these storms may anchor to specific terrain features and focus their precipitation over preferred areas. In particular, quasi-stationary precipitation bands are a manifestation of orographic convection that greatly increases flood risks because they focus heavy precipitation over specific regions. Such events are of particular concern over orographic watersheds, which, due to their steep gorges and confined basins, are highly susceptible to floods.
Thanks to the high resolution radar systems, quasi-stationary convective bands have been observed over numerous mountain regions including Japan, the Mediterranean region, Rocky Mountains, Pacific Northwest United States, and Caribbean islands. The hydro-meteorological importance of these bands is reflected by the planned installation of a dedicated observational network for banded orographic convection over the French Massif Central during the upcoming Hydrological Cycle in the Mediterranean (HyMEX) programme. Although these bands also develop regularly over the UK, they have received little previous attention. Moreover, the majority of previous studies have focused on specific cases and have not generally identified the environmental conditions that favour their formation, the mechanisms that cause them to develop, or their predictability in numerical models.
The proposed work will provide a leap forward in the understanding and prediction of quasi-stationary orographic convection in the UK and beyond. This will be achieved through an intensive climatological analysis over several regions of the globe where continuous radar data is available, which will identify the environmental conditions that support the bands and their characteristic locations and morphologies. Complementary high-resolution numerical simulations will pinpoint the underlying mechanisms behind the bands and their predictability in numerical weather prediction models. This work will provide positive impacts for the forecasting community, general public, and other academics in the field. Forecasters will benefit from the identification of simple diagnostics that can be used operationally to predict these events based on available model forecasts and/or upstream soundings. A series of activities are proposed to directly engage with forecasters to effectively disseminate our findings. The public will benefit from improved forecasting of potentially hazardous precipitation events. The academic community will benefit from the advanced physical understanding (which will be disseminated through conferences, workshops, and peer-reviewed publications) and the numerous international collaborations associated with this project.
Thanks to the high resolution radar systems, quasi-stationary convective bands have been observed over numerous mountain regions including Japan, the Mediterranean region, Rocky Mountains, Pacific Northwest United States, and Caribbean islands. The hydro-meteorological importance of these bands is reflected by the planned installation of a dedicated observational network for banded orographic convection over the French Massif Central during the upcoming Hydrological Cycle in the Mediterranean (HyMEX) programme. Although these bands also develop regularly over the UK, they have received little previous attention. Moreover, the majority of previous studies have focused on specific cases and have not generally identified the environmental conditions that favour their formation, the mechanisms that cause them to develop, or their predictability in numerical models.
The proposed work will provide a leap forward in the understanding and prediction of quasi-stationary orographic convection in the UK and beyond. This will be achieved through an intensive climatological analysis over several regions of the globe where continuous radar data is available, which will identify the environmental conditions that support the bands and their characteristic locations and morphologies. Complementary high-resolution numerical simulations will pinpoint the underlying mechanisms behind the bands and their predictability in numerical weather prediction models. This work will provide positive impacts for the forecasting community, general public, and other academics in the field. Forecasters will benefit from the identification of simple diagnostics that can be used operationally to predict these events based on available model forecasts and/or upstream soundings. A series of activities are proposed to directly engage with forecasters to effectively disseminate our findings. The public will benefit from improved forecasting of potentially hazardous precipitation events. The academic community will benefit from the advanced physical understanding (which will be disseminated through conferences, workshops, and peer-reviewed publications) and the numerous international collaborations associated with this project.
Planned Impact
Terrain-locked convective rainbands are important flood-producing features that give rise to heavy precipitation over many different parts of the globe including the UK. Their accurate prediction is essential because of the flooding and hazardous road conditions that they can produce. Because of their sensitivity to uncertainties in the initial flow field and to small-scale turbulent eddies that are unresolved even in today's highest-resolution operational weather forecasts, the bands represent a fundamental forecasting challenge. The ability of state-of-the-art operational forecast models (such as the Met Office's Unified Model with a grid-length of 1.5 km) to forecast these storms has not been evaluated; we will quantify the predictability of these bands in these models. Their climatological characteristics and thus importance relative to other types of precipitation are also presently unknown; we will construct and synthesize a multi-region climatology of these bands. We will also identify the general environmental conditions and physical mechanisms that lead to bands and control their evolution. This will enable us to provide guidance to forecasters on predicting the formation of these rainbands from low-resolution model forecasts and/or upstream soundings. This will be valuable information for operational forecast centres engaging in short-range forecasting using a range of resolutions and models. We intend to visit twice with Met Office operational forecasters over the course of this project to learn about their current approach for forecasting these events and then to provide tangible guidelines that will help them to refine their practice in the future. Additional dissemination activities include a forecaster-focused workshop and a scientific paper that targets the forecasting community.
Because of the potential socio-economic impacts of the hazardous weather associated with this mountain convection, the findings of this project will also be of interest to users with the responsibility for the mitigation of and response to these impacts. These include DEFRA, the environment agency, utilities providers such as power companies, and the insurance industry. The general public is also interested in the accurate forecasting of orographic convection. Events such as the Carlisle flood in 2005 and Cumbria floods in 2009 highlight the risks of extreme orographic precipitation events.
Because of the potential socio-economic impacts of the hazardous weather associated with this mountain convection, the findings of this project will also be of interest to users with the responsibility for the mitigation of and response to these impacts. These include DEFRA, the environment agency, utilities providers such as power companies, and the insurance industry. The general public is also interested in the accurate forecasting of orographic convection. Events such as the Carlisle flood in 2005 and Cumbria floods in 2009 highlight the risks of extreme orographic precipitation events.
People |
ORCID iD |
David Schultz (Principal Investigator) |
Publications
Barrett A
(2014)
Synoptic versus orographic control on stationary convective banding
in Quarterly Journal of the Royal Meteorological Society
Beukenhorst AL
(2020)
Are weather conditions associated with chronic musculoskeletal pain? Review of results and methodologies.
in Pain
Dixon WG
(2019)
How the weather affects the pain of citizen scientists using a smartphone app.
in NPJ digital medicine
Fairman J
(2017)
Build Your Own Earth: A Web-Based Tool for Exploring Climate Model Output in Teaching and Research
in Bulletin of the American Meteorological Society
Fairman J
(2015)
A radar-based rainfall climatology of Great Britain and Ireland
in Weather
Flint S
(2016)
Sedimentological and Paleoclimate Modeling Evidence for Preservation of Jurassic Annual Cycles in Sedimentation, Western Gondwana
in Earth Interactions
Hardy S
(2017)
Early Evolution of the 23-26 September 2012 U.K. Floods: Tropical Storm Nadine and Diabatic Heating due to Cloud Microphysics
in Monthly Weather Review
Kelley J
(2019)
Can Mountain Waves Contribute to Damaging Winds Far Away from the Lee Slope?
in Weather and Forecasting
Kirshbaum D
(2018)
Convective Cloud Bands Downwind of Mesoscale Mountain Ridges
in Journal of the Atmospheric Sciences
Kirshbaum D
(2015)
Cloud Trails Past the Lesser Antilles
in Monthly Weather Review
Description | What we have found in this research is exactly how difficult it is to predict rain downstream of mountains that form in lines of storms. These lines of storms may produce heavy rain or snow, yet our ability to predict them is limited. In this research, we examined how well the Met Office models do at predicting these bands in several cases and found that they do really poorly, worse perhaps than they should. This surprising result suggests that something is seriously flawed in the way that these bands form and remain stationary. Another thing that this research found is where in the UK such banded precipitation occurs. Bands occur mostly over the Irish Sea and English Channel. We now have climatologies of banded precipitation in both the British Isles and the USA. |
Exploitation Route | Improvements in the Met Office model. Comparison between Met Office model and WRF, which seems to do a better job at predicting bands. |
Sectors | Aerospace, Defence and Marine,Education,Energy,Environment,Leisure Activities, including Sports, Recreation and Tourism,Transport |
URL | http://www.met.reading.ac.uk/~mwp/meso/Research/presto.html |
Description | The Met Office has used our findings to better understand the weaknesses in their forecast model. |
Sector | Aerospace, Defence and Marine,Construction,Education,Energy,Environment,Leisure Activities, including Sports, Recreation and Tourism,Transport |
Impact Types | Societal |
Description | NERC/NCAS Legacies Fund |
Amount | £295 (GBP) |
Organisation | National Centre for Atmospheric Science (NCAS) |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 06/2014 |
End | 07/2014 |
Title | The release of inertial instability near an idealized zonal jet |
Description | Inertial instability is a hydrodynamic instability that occurs in strong anticyclonic flow and is typically diagnosed by negative absolute vorticity in the Northern Hemisphere. As such, inertial instability is often observed on the anticyclonic-shear side of jet streams, yet the release of the instability in this environment is still poorly understood. We simulate the release of inertial instability near an idealized midlatitude zonal jet compared a control simulation with no instability. We find that the release of the instability results in flat meridional wind perturbations of up to 7 m/s over 200 km that persist for several days, in addition to radiating inertia-gravity waves several hundreds of kilometers away from the unstable region. Furthermore, these perturbations instigate light-moderate occurrences of clear-air turbulence around the unstable region that persist for up to 12 hours. |
Type Of Material | Database/Collection of data |
Year Produced | 2021 |
Provided To Others? | Yes |
URL | http://datadryad.org/stash/dataset/doi:10.25349/D9532W |
Description | Met Office partnership |
Organisation | Meteorological Office UK |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Helped improve understanding of the Met Office ensembles and their ability to predict banded orographic precipitation Seminars at the Met Office describing research results |
Collaborator Contribution | Knowledge of model behavior Training of students and postdocs on model Coauthorship of research articles |
Impact | Barrett et al. (2015) in the Quarterly Journal of the Royal Meteorological Society : collaboration is not multi-disciplinary |
Start Year | 2011 |
Description | DOMEX Workshop |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | Yes |
Geographic Reach | Regional |
Primary Audience | Other academic audiences (collaborators, peers etc.) |
Results and Impact | Talk sparked questions and discussion afterwards None. |
Year(s) Of Engagement Activity | 2014 |
URL | http://www.domex2011.com/ |
Description | Insights into thermally forced mountain convection |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Participants in your research or patient groups |
Results and Impact | Invited talk at Dalhousie University Invited oral presentation on research projects done by Dan Kirshbaum, including PRESTO research. |
Year(s) Of Engagement Activity | 2014 |
Description | The Generation of Downwind Rainbands by Mountains |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | Yes |
Geographic Reach | National |
Primary Audience | Postgraduate students |
Results and Impact | None. |
Year(s) Of Engagement Activity | 2014 |
Description | University of Reading Capabilities in Weather Research |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Professional Practitioners |
Results and Impact | Sue presented to British Telecomm the results of Andrew Barrett's research, with the goal of developing collaborations with BT. None. |
Year(s) Of Engagement Activity | 2014 |
Description | Update on PRESTO activities |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Participants in your research and patient groups |
Results and Impact | Presentation at Reading University None. |
Year(s) Of Engagement Activity | 2014 |