ANALYSIS OF AGROCLIMATIC SPATIAL AND TEMPORAL VARIABILITY AT FARM SCALE

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ANALYSIS OF AGROCLIMATIC SPATIAL AND TEMPORAL
VARIABILITY AT FARM SCALE
Simone Orlandini, Anna Dalla Marta, Marco
Mancini, Alessio Orlandini Department of
Agronomy and Land Management University of
Florence
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• One of the key elements for an efficacious
  territorial characterization and monitoring is
  represented by a correct design of the
  agrometeorological station network.
• At the moment, the applied criteria are mainly
  based on economic costs, accessibility,
  representativeness of the surrounding vegetation,
  distance from obstacles and control.

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WHERE?
MONITORING LENGTH
AGROMETEOROLOGICAL STATIONS POSITIONING
HOW LONG?
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3
2
4
N years
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AIMS

• Analysis of temperature spatial variability to
  determine the relationships between neighbouring
  stations and the causes of the observed
  variability, in order to identify the criteria
  for a correct stations positioning
• Definition of the minimum length of the
  monitoring period to obtain a representative
  description of the relations among the different
  measuring points

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METHODS

• The research has been carried on in a small area
  of about 120 ha, in order to obtain information
  at farm scale
• The approach proposed by Hubbard, based on the
  analysis of the determination coefficient (R2),
  has been followed
• A temperature data set of 8 years (1996 - 2003)
  was available for 28 positions

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Thermo-hygrometric network Fattoria Poggio
Casciano
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(No Transcript)
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AVAILABLE LAYERS
Altitude Aspect Distance from valleys bottom Slope
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SPATIAL VARIABILITY ANALYSIS

• Reference station identification
• - the lowest position ( 150 m asl)
• - the most representative
• Calculation of R2 between the reference station
  and the other measuring points
• Graphic representation of variograms on monthly
  bases (8 years average) for Tmax, Tmin and Tmean.
  The R2 values have been distributed as function
  of
• distance
• difference in height
• distance from valley bottom
• aspect

absolute and real values
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Belt positioning-absolute values
High belt
60 m
Medium belt
35 m
Low belt
Reference station position
-35 m
Medium belt
-60 m
High belt
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Belt positioning-relative values
High belt
20 m
Medium belt
Reference station position
-20 m
Low belt
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Minimum temperature - altitude
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Mean temperature - altitude
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Maximum temperature - altitude
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Distance from valley bottom
Minimum
Mean
Maximum
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T mean
Aspect
Distance
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Minimum temperature
R2
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Mean temperature
R2
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Maximum temperature
R2
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TEMPORAL VARIABILITY ANALYSIS

• Calculation of R2 between pairs of stations using
  average data from a progressively longer period
  of time (from 1 to 8 years)
• Identification of the time period necessary for
  the temporal variability stabilization of the
  measured variables, in order to obtain
  information representative of the differences
  existing within the study area

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November maximum temperature
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CONCLUSIONS

• The described method has provided important
  information on the spatial and temporal
  distribution of temperature at small scale and on
  criteria to design monitoring network
• To complete the analysis and obtain detailed
  information on the existing variability, other
  agrometeorological variables have to be
  considered
• The results will represent the basis for the set
  up of standard protocols for the creation of
  monitoring networks at farm scale, in order to
  obtain information without long and complicated
  preliminary analysis