The Application of In-Situ Observations to Weather, Water, and Climate Issues

Ken Crawford

Vice Administrator

Korea Meteorological Administration

WMO Technical Meeting

Seoul, Republic of Korea

16 November 2009

This presentation will use in-situ observations from a wide-area network to illustrate their value in determining the water budget of a given locale.

(With some technical slides provided by Dr. Jeff Basara from the University of Oklahoma)

The Oklahoma Mesonet Oklahoma’s Weather and Climate network of 120 sites Deployed across 181,186 km2 and commissioned in 1994 Joint project between the Oklahoma State University and the

University of Oklahoma. Extensive quality assurance is applied to the collected observations

(real-time and archived automated and manual) Over 4 billion observations archived Operational funding supplied by the State of Oklahoma – Research

funded mainly by grant awards More than 370 peer-reviewed publications, over 80 M.S. theses,

and over 30 Ph.D. Dissertations have used Oklahoma Mesonet data

The Oklahoma Mesonet

• Every 5 minutes:– Air temperature, 1.5 m, 9 m – Relative humidity, 1.5 m– Rainfall (tipping bucket)– Barometric pressure– Solar, net radiation, 1.8 m– Wind speed/direction, 10 m – Wind speed, 2 m, 9 m– Skin temperature, 1.5 m

• Every 15 minutes:– 5 cm soil temp, bare soil, native sod– 10 cm soil temp, bare soil, native sod– 30 cm soil temp, native sod

• Every 30 minutes:– 5 cm soil moisture (108 Sites)– 25 cm soil moisture (106 Sites)– 60 cm soil moisture (81 Sites)– 75 cm soil moisture (32 Sites)

McPherson, R. A., C. Fiebrich, K. C. Crawford, R. L. Elliott, J. R. Kilby, D. L. Grimsley, J. E. Martinez, J. B. Basara, B. G. Illston, D. A. Morris, K. A. Kloesel, S. J. Stadler, A. D. Melvin, A.J. Sutherland, and H. Shrivastava, 2007: Statewide monitoring of the mesoscale environment: A technical update on the Oklahoma Mesonet. J. Atmos. Oceanic Tech., 24, 301–321.

Linear Relationships Between Root Zone Soil Moisture and Surface Heat Fluxes

Basara, J.B., and K.C. Crawford, 2002: Linear relationships between root-zone soil moisture and atmospheric processes in the planetary boundary layer. J. Geophys. Rsch., 107, ACL 10-1-18, 879-884.

0 0.2 0.4 0.6 0.8 1

0-5

5-10

10-20

20-30

30-40

40-50

50-60

60-70

70-80

Explained Variance Between Mean Soil-Water Content and Daily-Maximum of Heat Fluxes at the Norman Mesonet Site

SHLH

Explained Variance

Soil Depth (cm)

Linear Correlation of Sensible and Latent Fluxes With Respect To Soil-Water Content and Soil Depth

Evapotranspiration The combined impacts of evaporation and transpiration which

remove water from the “surface” to the atmosphere.

Requires “energy” for liquid water to change phase to water vapor.

Is highly dependent on solar radiation (sunlight), temperature, wind speed, and ambient humidity.

Is a critical component of the water cycle and may be a source for subsequent precipitation.

Estimated using observed Oklahoma Mesonet observations and the ASCE standardized reference (potential) ET equation (Penmann-Monteith).

The Oklahoma Mesonet - 15 Years

The Oklahoma Mesonet - 15 Years

(Potential ET)

The Oklahoma Mesonet - 15 Years

The Oklahoma Mesonet - 15 Years

The Oklahoma Mesonet - 15 Years

I II III IV I

I II III IV I

Phase I – Minimal ET, Limited Precipitation, Soils are Relatively Moist

I II III IV I

Phase II – Increasing ET, Increasing Precipitation, Soils Begin to Dry

I II III IV I

Phase III – Near Peak ET, Precipitation Significantly Decreases,Soils Dry Rapidly

I II III IV I

Phase IV – ET Decreases, Precipitation Increases Slightly,Soils Begin to Recharge

The Diurnal Cycle of Land-Atmosphere InteractionsAcross Oklahoma’s Winter Wheat Belt

M A T T H E W J. H A U G L A N D

Matt HauglandAcross Oklahoma’s Winter Wheat Belt

The Diurnal Cycle of Land-Atmosphere Interactions

What is Oklahoma’s Winter Wheat Belt?

Matt HauglandAcross Oklahoma’s Winter Wheat Belt

The Diurnal Cycle of Land-Atmosphere Interactions

What is Evapotranspiration (ET) ?

Transpiration Evaporation

Roots draw soilMoisture up intothe plant

IncreasesLatent HeatFlux

And why is it important?

R – G = H + LER – G = H + LE(Surface energy balance)

Matt HauglandAcross Oklahoma’s Winter Wheat Belt

The Diurnal Cycle of Land-Atmosphere Interactions

Before Harvest – Healthy Wheat Crop

• The Winter Wheat Belt is greener than the adjacent counties.• Latent Heat Flux across the WWB is higher (Sensible Heat Flux is lower)• Average high temperatures across the WWB are lower.

Visual Greenness (April 2000)

Matt HauglandAcross Oklahoma’s Winter Wheat Belt

The Diurnal Cycle of Land-Atmosphere Interactions

March 1994-2000 (0000 – 1300 UTC) Before Harvest - Average Dewpoint Change

Matt HauglandAcross Oklahoma’s Winter Wheat Belt

The Diurnal Cycle of Land-Atmosphere Interactions

8 April 2000 (0000 – 1300 UTC) Before Harvest – Ideal Day Dewpoint Change

Matt HauglandAcross Oklahoma’s Winter Wheat Belt

The Diurnal Cycle of Land-Atmosphere Interactions

After Harvest– Bare Soil & Dead Wheat Stubble

Visual Greenness (June 2000)

• The Winter Wheat Belt is less green than the adjacent counties.• Evapotranspiration across the WWB is lower• Sensible heat flux across the WWB is higher

Matt Haugland

Across Oklahoma’s Winter Wheat BeltThe Diurnal Cycle of Land-Atmosphere Interactions

June 1994-2000 (2300 – 1100 UTC) After Harvest – Average Dewpoint Change

Matt HauglandAcross Oklahoma’s Winter Wheat Belt

The Diurnal Cycle of Land-Atmosphere Interactions

8 June 2000 (2300 – 1100 UTC) After Harvest – Ideal Day Dewpoint Change

These results:

Provide important, current baselines for many critical variables that impact the water balance of a given locale;

Provide increased understanding of the critical water budget components needed for a comprehensive water plan for Oklahoma; and

Begin to close the gap between our understanding of water as it relates to climate in Oklahoma.

Hopefully, these results also show the great scientific value that in-situ observations offer to those who study weather, water, and climate issues.

Summary

Questions?