In this work, the joint probabilities and return periods of two characteristics - Duration, D (days) and Severity, S (mm) - of the simulated water stress in olive orchards were modelled by a two-dimensional copula. First, the precipitation and temperature daily time series of some stations in central Italy were used in input to a “bucket” soil water balance model to simulate the corresponding dynamics of the soil water (SW) available for olive. Then, by applying the theory of runs to SW, with a threshold equal to the crop critical point, the water stress events were identified and characterized in terms of D (days) and S (mm). This last variable is given by the sums of the daily evapotranspiration deficit during the corresponding water stress event. A 2-parameter Gamma distribution was fitted to both D and S, whilst their dependence structure was modelled by a Student’s t copula. Finally, the stations considered were compared in terms of joint probabilities and joint return periods for D and S, thus enabling the evaluation and the characterization of the risk of water stress related to olive in different areas.
BIVARIATE ANALYSIS OF THE DURATION AND SEVERITY OF WATER STRESS IN OLIVE
VERGNI, LORENZO
;
2017
Abstract
In this work, the joint probabilities and return periods of two characteristics - Duration, D (days) and Severity, S (mm) - of the simulated water stress in olive orchards were modelled by a two-dimensional copula. First, the precipitation and temperature daily time series of some stations in central Italy were used in input to a “bucket” soil water balance model to simulate the corresponding dynamics of the soil water (SW) available for olive. Then, by applying the theory of runs to SW, with a threshold equal to the crop critical point, the water stress events were identified and characterized in terms of D (days) and S (mm). This last variable is given by the sums of the daily evapotranspiration deficit during the corresponding water stress event. A 2-parameter Gamma distribution was fitted to both D and S, whilst their dependence structure was modelled by a Student’s t copula. Finally, the stations considered were compared in terms of joint probabilities and joint return periods for D and S, thus enabling the evaluation and the characterization of the risk of water stress related to olive in different areas.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
