Local%20Climate%20Estimator

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Local Climate Estimator
LocClim
Jürgen Grieser
And The Agromet Group
And Jeroen Ticheler

• Environment and Natural Resources Service
• SDRN

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Local Climate Estimator
Estimates the Climate at a given location.
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Why should this be important?

• In order to investigate climatic constraints.
• investigate deviations from Normal states.
• compare different locations.

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Why should this be a difficult problem?

• Climate is highly variable in time and space.
• This variability happens to occur on all scales.

- Pole/Equator
- South/North of a tree
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How does LocClim estimate the local climate?
How gooddoes LocClim estimate the local climate?
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How to estimate the climate of a given location?

• Nearest-Neighbor Approximation

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How to estimate the climate of a given location?

• Nearest-Neighbor Approximation

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How to estimate the climate of a given location?

• Simple Averaging

Fixed number of neighbors
Fixed maximum distance
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How to estimate the climate of a given location?

• Weighted Averaging
• Inverse Distance

Observations
Distance
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How to estimate the climate of a given location?

• Weighted Averaging
• Inverse Distance

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How to estimate the climate of a given location?

• Weighted Averaging
• Inverse Distance
• According neighborhood (shadowing)

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How to estimate the climate of a given location?

• Weighted Averaging
• Inverse Distance
• According neighborhood (shadowing)
• According to altitude

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How to estimate the climate of a given location?

• Systematic Approximations
• Altitude Functions

Altitude
Observations
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How to estimate the climate of a given location?

• Systematic Approximations
• Horizontal Functions

Observations
Horizontal Coordinates
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Which method is the best?

• Nearest Neighbor
• Simple Averaging
• Inverse Distance Weighted Averaging
• Shadow Controlled Averaging
• Systematic Altitude Function
• Systematic Horizontal Function

There is no general answer!
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What is LocClim doing?

1. Altitude Correction to reduce all obseravtions to
   the Altitude of the desired location.

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What is LocClim doing?

1. Altitude Correction to reduce all obseravtions to
   the Altitude of the desired location.

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What is LocClim doing?

1. Altitude Correction to reduce all obseravtions to
   the Altitude of the desired location.

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What is LocClim doing?

1. Altitude Correction to reduce all obseravtions to
   the Altitude of the desired location.

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What is LocClim doing?

1. Altitude Correction to reduce all obseravtions to
   the Altitude of the desired location.

Altitude
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What is LocClim doing?

1. Altitude Correction

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What is LocClim doing?

1. Altitude Correction
2. Horizontal Correction

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What is LocClim doing?

1. Altitude Correction
2. Horizontal Correction

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What is LocClim doing?

1. Altitude Correction
2. Horizontal Correction

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What is LocClim doing?

1. Altitude Correction
2. Horizontal Correction
3. Inverse Distance Weighted Averaging

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What is LocClim doing?

1. Altitude Correction
2. Horizontal Correction
3. Inverse Distance Weighting
4. Shadow Controlled Weighting

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How good is the estimate?

• Depends on region and climate variable
• LOCLIM only estimates the expectation value of
  the observation - not the truth.

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Quality Assessment
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Quality Assessment
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Quality Assessment

• Calculate the estimation error at every station
• Average Error Bias
• Variability Local Climate Variability

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Quality Assessment

• Never trust extrapolated data.

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Quality Assessment

• Never trust extrapolated data.

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Quality Assessment

• Never trust extrapolated data.

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Quality Assessment

• Never trust extrapolated data.

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Quality Assessment

• Never trust extrapolated data.

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Quality Assessment

• Never trust extrapolated data.

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Quality Assessment

• Never trust extrapolated data.

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Are there enough data?
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Global Database(maintained by Fulvia Petrassi,
The Agromet Group)
Variable (Monthly Values) Number of stations Max. Distance (km) if homogeneously distributed
Mean Temperature 20828 49 km
Minimum Temperature 11550 65 km
Maximum Temperature 11544 65 km
Precipitation 27375 43 km
Potential Evapotranspiration 4285 107 km
Windspeed 3779 114 km
Vapor Pressure 3959 111 km
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Lets try it!
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(No Transcript)
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Maximale Entfernung bei gleichmäßiger Verteilung
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Maximale Entfernung bei gleichmäßiger Verteilung
Variable Max. Entfernung Stationen
Temp. 49 km 20828
Min. T. 65 km 11550
Max. T. 65 km 11544
Nieder. 43 km 27375
PET 107 km 4285
Wind 114 km 3779
Dampf 111 km 3959
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Mögliche Fehlerquellen

• Systematische Fehler
• - Horizontalgradient der Variable
• - Vertikalgradient der Variable
• - ...
• Statistische Fehler
• - Durch lokale Schwankungen
• - Durch Ausreißer (Ort, Wert)
• - ...
• Behandlung mit Jackknife-Verfahren

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How does the climate look likeat any location on
Earth?

• Investigate climatic constraints
• Investigate deviations from normals (average
  conditions)
• Compare different locations