1. Regional Weather and Climate Data

2. Weather and Climate
Climate is a key driver of ecological and hydrological processes
Climate variables form one of the most important set of inputs for environmental models
Surface air temperature
Precipitation
Surface air humidity
Incident shortwave radiation
Problems:
Meteorological variables rarely observed at locations of interest
Weather observation points have relatively low spatial density
Spatial data products often do not match spatial and/or temporal scale of research

3. Scales of Weather and Climate
Time Scale
Spatial Scale
Example
Macroscale
Weeks or longer
1000 – 40,000 km
Westerlies, Trade Winds
Synoptic
Days to weeks
500 – 5000 km
Mid-latitude cyclones, anticyclones
Mesoscale
Minutes to hours
1 – 100 km
Land-sea and mountain/valley breezes
Microscale
Seconds to minutes
< 1 km
Dust devils, gusts

4. Point Source Weather/Climate Observations
Weather Stations
NOAA NWS
NCDC
SNOTEL
RAWS

5. Point Source Weather/Climate Observations
Radiosondes: Provide vertical profile measurements of the atmosphere
Pressure
Temperature
Humidity
Winds

6. Spatially Continuous Weather/Climate Observations
Doppler Radar: a type of radar that has the capacity to not only detect the occurrence of precipitation, but also its velocity towards or away from the radar
Conventional radar transmits short pulses of microwaves. The strength and timing of the return signal indicates precipitation intensity and location.

7. Spatially Continuous Weather/Climate Observations
Satellite
NASA Tropical Rainfall Measuring Mission (TRMM)
GPM
NASA TRMM

8. MODELS

9. Models: Statistically Interpolated Datasets
Landscape scale interpolations
PRISM
DAYMET
wxTopo (NTSG and Montana Climate Office)
Site
Base Station
I wonder what the weather is like up there?
Extrapolate

10. Models: Statistically Interpolated Datasets
Station Data
Basic Process: Daymet example
Digital Elevation Model

11. Models: Statistically Interpolated Datasets
Standard Environmental Lapse Rate
6.5°C/1000m

12. Temperature Inversions
How does an inversion form?
Radiation Inversion: on cold clear calm nights LWR can radiate from the ground quickly, escape into upper atmosphere and the air near the surface will be very cool (usually very shallow).

13. Temperature Inversions
How does an inversion form?
Cold-Air Drainage: cold air sinking into valleys can lead to inversions. Cold air is more dense than warm air. This causes the cold air to “drain” (like water) downhill!

14. Thermal Belts

17. Gstettneralm Sinkhole, Austria Elevation = 1270 m 21 January 1930
-1.8°C
-3.7°C
150 m
+2.3°C
-1.1°C
-12.4°C
-15.6°C
-28.8°C
All time temperature difference record!
Small valley in Switzerland – vertical distance from here to the “M”
At top of valley – about 1C (34 F),
as go into valley, -30C (30 BELOW ZERO!!) (-22 F)
extreme case of cold air drainage!
Gstettneralm Sinkhole, Austria
Elevation = 1270 m
21 January 1930
Coldest temperature = °C (-63 °F)
Photo: Bernhard Pospichal,
November 2001

18. Process-Based Models Numerical Weather Prediction Models
Used to provide typical weather forecasts Medium-Range (~ 7 days out)
Global Forecast System (GFS)
ECMWF Integrated Forecast System (IFS)
Canadian Global Environmental Multiscale Model (GEM)
Short-Range (~3 days)
North American Mesoscale Model (NAM)

19. Reanalysis Data
Reanalysis Datasets: combine assimilation of past observations and a numerical weather prediction model to produce an historical 3-D spatial dataset
Synoptic/mesoscale

20. El Niño-Southern Oscillation (ENSO)
A system of interactions between the tropical Pacific Ocean and the atmosphere above it
El Niño: warm phase
La Niña: cold phase
Interval of El Niño occurrence is 3 – 5 years but can be anywhere from 2 – 12 years
Produces the greatest interannual variability of temperature and precipitation on a global scale

21. ENSO “Normal” tropical Pacific conditions
The strength and location of the jet streams over both the North and South Pacific. This influence on the jet streams tends to be most pronounced during the respective hemisphere's winter season, when both the location and eastward extent of the jets (to just east of the date line) exhibit a strong relationship to the pattern of tropical heating. These jet streams are then a major factor controlling the winter weather patterns and storm tracks in the middle latitudes over both North and South America.
For both El Niño and La Niña the tropical rainfall, wind, and air pressure patterns over the equatorial Pacific Ocean are most strongly linked to the underlying sea-surface temperatures, and vice versa, during December-April. During this period the El Niño and La Niña conditions are typically strongest, and have the strongest impacts on U.S. weather patterns.
El Nino and La Niña episodes typically last approximately 9-12 months. They often begin to form during June-August, reach peak strength during December-April, and then decay during May-July of the next year. However, some prolonged episodes have lasted 2 years and even as long as 3-4 years. While their periodicity can be quite irregular, El Niño and La Niña occurs every 3-5 years on average.

22. ENSO
“Normal” tropical Pacific conditions

23. ENSO
El Niño Conditions

24. El Niño/ La Niña Impacts
Shift in jet streams

25. El Niño Impacts El Niño effect during December through February
El Niño effect during June through August

26. La Niña Impacts La Niña effect during December through February
La Niña effect during June through August

27. ENSO Multivariate ENSO Index Outlook
Currently in ENSO-neutral conditions
Enso-neutral is favored into summer 2013