unstable, dri and water cycling ronald stewart mcgill university

UNSTABLE, DRI UNSTABLE, DRI and Water Cyclingand Water Cycling

Ronald StewartMcGill University

Specific Objectives of Presentation

• To briefly review DRI and some of its science

• Comment on interactions with UNSTABLE

Prairie Drought

CONCERNS

There are many concerns associated with drought but many of these can be summarized under two broad categories

• Will there be a drought?decadelseasonal‘now’

• How do we best prepare for and cope with drought?

many perspectives

WATER AND ENERGY CYCLING

Drought is an aberration in theWater and energy cycle

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DRI Objective• To better understand and contribute to the

better prediction of drought …

• Focus mainly but not exclusively on the

recent 1999-2005 Prairiedrought

DEUTERIUM IN WATER VAPOUR

550-800 hPa layer

Tropospheric Emission Spectrometer: Aqua satellite

Days with precipitationCalgary

• The fraction of days receiving any amount of precipitation:

Climatology (1895-2004): 40%

Drought (1999-2004): 46%

Sub-Drought (2001-2002): 43%

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Climatology

Low precipitation events: 52% of total

Sub-drought 2001-2002

Low precipitation events: 60% of total

Daily Precipitation AmountsCalgary Low precipitation event:

< 10 mm

What factors led to the ≤10 mm events?

Possibilities include

• Loss due to evaporation/sublimation• Short-lived weather systems• Change in character of clouds• Fast moving weather systems• …

RADAR PROFILES1 June 2002: Calgary

• Scattered stratiform rain early

• Late in the day there is evidence of water aloft (~5 km)

• This appears to be high-level moisture as a precursor to the rainy pattern on the following day

VIRGA

Courtesy of Barrie Bonsal

VEGETATION

July 11-20, 2002

NDVI

NDVI: Normalized DifferenceVegetation Index

Healthy vegetation

UNSTABLE

Sub-objectives include …

to better understand, resolve, and quantify:

• spatial extent, depth and temporal evolution of water vapour in the atmospheric boundary layer

• Mesoscale effects on thunderstorms• effects of variable surface• …

DRI and UNSTABLE

• DRIdiverse research expertise (~ 30)datasets (atmosphere, surface …)analysis tools (DAI …)…

• UNSTABLEaspects linked with water cyclingfocused activityobservational and model products…

CONCLUDING REMARKS

• DRI is concerned with:the science of water cycling

• UNSTABLE is concerned with:overturning of the atmosphere

• DRI and UNSTABLE can benefit from collaboration

And … thank you for your attention