# Presentation: 401139

## The Adequacy of Urban Weather Observations: A View Based on Oklahoma Mesonet Experiences

- Ken Crawford, Program Director
- Integrated Surface Observing Systems
- NWS Office of Science and Technology
- Presented at the “Challenges in Urban Meteorology: A Forum for Users and Providers”
- September 21, 2004

## Answers to the Following Questions

- Are Based Upon:
- 15 years in planning, operating and maintaining the Oklahoma Mesonet
- 25 MS theses and Ph. D. dissertations built around data from the Oklahoma Mesonet and produced by my graduate students
- 11 years in operating a K-12 outreach program and 8 years in operating an award-winning public safety program — both built around the OK Mesonet
- 15 years as an operational forecaster for the NWS
- 2-3 years spent in planning COOP modernization and the building of a National Mesonet

## Questions and Answers

- 	_**QUESTION:**_ What are the requirements for timeliness, accuracy, and precision for urban applications of meteorological information? Do current observing systems meet these requirements?
*Timeliness:* 5 minute observations prior to 2010; 1 minute or less for observations from 2010 and beyond
*Accuracy/Precision:*
- Temperature — 0.3 oC & 0.01 oC
- Wind Speed — 2% of reading & 0.03 m/sec
- Wind Direction — 3o & 0.05o
- Humidity — 3% & 0.03%
- NO!!

## Questions and Answers

- 	_**QUESTION:**_ Where current observing systems do not meet urban requirements, which unmet needs have the highest priority?
- Stations must be properly sited — even urban sites
- High resolution data are needed — spatial and temporal
- Numerous variables must be measured — Need more than just temperature, wind and humidity (e.g., must measure components of the surface energy budget; radiometric temperature; air quality observations)
- Data Quality-Assurance is critical
- Data must be available in the public domain within 1-2 minutes of its collection

## Questions and Answers

- 	_**QUESTION:**_ What are the major challenges in collecting, processing, assimilating, and communicating urban weather observations to meet urban users’ requirements?
*Collecting:* Are we using highly reliable systems that work under the most adverse of conditions (e.g., RF radio links to LETS agencies)?
*Processing:* Are we using high-end PCs with multiple units handling distributed tasks?
*Assimilating:* Have we remembered the ultimate user?
*Communicating:* Have we remembered the ultimate user?

## Questions and Answers

_**QUESTION: **_Are the education, training and outreach challenges related to weather observations being addressed?
- No, not really. This process is incredibly uneven across the United States. Two primary weaknesses exist:
- Data and information are not communicated in a form/format that users need/want. (e.g., all images should be *under the control* of local users/first responders)
- Formal training programs are practically non-existent
- Shameless Commercial: There are some model programs in existence — OK-FIRST is one and it was honored by Harvard University as “one of the five-most innovative programs in American Government” in 2001

## We Must Use What We Have More Efficiently

- For Example...

## Mesonet Site Locations

- “Wheat” Sites
- “West” Sites
- “East” Sites

- The wheat-belt, after harvest, functions like an urban heat island during the afternoon.

**Notes:**
Figure 3.4, p. 35

## Reverse Inland “Sea breeze” Circulation

- SOM Seminar – Matt Haugland

**Across Oklahoma’s Winter Wheat Belt**

- The Diurnal Cycle of Land-Atmosphere Interactions

**Reverse Inland “Sea breeze” Circulation**

**COOL**

**COOL**

**WARM**

**H**

**H**

**L**

**H**

**L**

**L**

- Divergence

- The city-center (i.e., the wheat belt) becomes warm during the afternoon and induces low-level convergence.

## Diurnal Temperature & Pressure Anomalies

- SOM Seminar – Matt Haugland

**Across Oklahoma’s Winter Wheat Belt**

- The Diurnal Cycle of Land-Atmosphere Interactions

- After Harvest, June 1994-2000

**(WWB – AC)**

**Diurnal Temperature & Pressure Anomalies**

- The result is an afternoon warm anomaly over the wheat belt and a co-located low pressure anomaly.

## Temperature(comparison between Micronet and nearby Mesonet sites)

***Temperature****(comparison between Micronet and nearby Mesonet sites)*

***MATT HAUGLAND***

- Pasture-Level Influences

- Note the cold anomaly mid-way between two Mesonet sites spaced 20 miles apart!

## The Impact of the Near-Sensor Environment on the Resulting Observations

**Several trees to the southeast of a site result in low measured values of radiation during the first several hours of the day.**

- Blue line: an unobstructed station

## The Impact of the Near-Sensor Environment on the Resulting

**A large transmission pole to the southeast of a site causes an obstruction to the pyranometer for about an hour each morning.**

- Observations

## Despite a negative wind speed anomaly from the NNW, Bixby has a positive temperature anomaly (4-6 F) with NNW winds. Possible cause: the Tulsa metro area is NNW of Bixby.

- But the wind obstructions appear to cause large negative temperature anomaly when wind does not come from Tulsa.
- Notice a warm spike with west winds - another town is upstream!

## The EndKenneth.Crawford@noaa.gov