ARPA Lombardia (Italy): Operational maps (temperature, relative humidity) Lombardia is located in... more ARPA Lombardia (Italy): Operational maps (temperature, relative humidity) Lombardia is located in the southern side of the Alps. The grid box is 264 Km x 260 Km. The grey tones show the orography, with the Alps in the North, the Appennines in the South, and the Po Plain in ...
The predictability of convective systems is limited by the rapidly evolving non-hydrostatic dynam... more The predictability of convective systems is limited by the rapidly evolving non-hydrostatic dynamics and by the strong non-linearities present in moist thermodynamics, associated to convection processes. The perspective of the study is to assess the applicability of advanced data assimilation methods like AUS (Assimilation in the Unstable Subspace, Trevisan and Uboldi, 2006), but also 4D-Var or EnKF, which were successfully applied to larger scales.
In una relazione relativa a un lavoro svolto in precedenza (Uboldi, 2006) sono stati descritti al... more In una relazione relativa a un lavoro svolto in precedenza (Uboldi, 2006) sono stati descritti algoritmi, scelte di implementazione e applicazioni a casi di studio relativi a una procedura di interpolazione spaziale di misure di temperatura, che è attualmente disponibile per uso ...
Le osservazioni meteorologiche, e, più in generale, ambientali, in Lombardia costituiscono una re... more Le osservazioni meteorologiche, e, più in generale, ambientali, in Lombardia costituiscono una rete osservativa caratterizzata da una elevata risoluzione, se confrontata con quella dei dati GTS. La rete lombarda attuale, come quella di altre regioni italiane, risulta da un ...
Francesco Uboldi consulente e ricercatore indipendente e-mail, home. Interpolazione spaziale di o... more Francesco Uboldi consulente e ricercatore indipendente e-mail, home. Interpolazione spaziale di osservazioni meteorologiche da reti regionali ad alta risoluzione Agosto 2008...con qualche aggiornamento (2010) Introduzione ...
A hybrid scheme obtained by combining 3DVar with the Assimilation in the Unsta- ble Subspace (3DV... more A hybrid scheme obtained by combining 3DVar with the Assimilation in the Unsta- ble Subspace (3DVar-AUS) is tested in a QG model, under perfect model conditions, with a fixed observational network, with and without observational noise. The AUS scheme, originally formulated to assimilate adaptive observations, is used here to as- similate the fixed observations that are found in the region
The status of the work and the recent results of the application of the Assimilation in the Unsta... more The status of the work and the recent results of the application of the Assimilation in the Unstable Subspace are reported with special emphasis to the analysis of the stability induced by the assimilation of observations.
The ability of a data assimilation system to control the instabilities, present in the forecast e... more The ability of a data assimilation system to control the instabilities, present in the forecast error and responsible for error growth, can be improved by the combination of targeting strategies and dynamically consistent assimilation. The benefit of adaptively located observations is greatly enhanced if their positions and their assimilation are designed in order to target the instabilities, estimated by Breeding on the Data Assimilation System (BDAS). The analysis update has locally the same structure as the unstable structure whose maximum is in the location chosen for the adaptive observation. In this way, advantage can also be taken of an existing, fixed observational network, as long as this is is adequate to detect the migrating instabilities. These concepts are demonstrated by means of observing system simulation experiments with a quasi-geostrophic atmospheric model and with a primitive equation oceanic model.
Estimation of extreme event distributions and depth-duration-frequency (DDF) curves is achieved a... more Estimation of extreme event distributions and depth-duration-frequency (DDF) curves is achieved at any target site by repeated sampling among all available raingauge data in the surrounding area. The estimate is computed over a gridded domain in Northern Italy, using precipitation time series from 1929 to 2011, including data from historical analog stations and from the present-day automatic observational network. The presented local regionalisation naturally overcomes traditional station-point methods, with their demand of long historical series and their sensitivity to very rare events occurring at very few stations, possibly causing unrealistic spatial gradients in DDF relations. At the same time, the presented approach allows for spatial dependence, necessary in a geographical domain such as Lombardy, complex for both its topography and its climatology. The bootstrap technique enables evaluating uncertainty maps for all estimated parameters and for rainfall depths at assigned re...
In recent years, the use of mesoscale meteorological network data has been growing. An Optimal In... more In recent years, the use of mesoscale meteorological network data has been growing. An Optimal Interpolation (OI) method is used to interpolate on a regular grid the hourly averaged values of temperature, relative humidity, wind vector, atmospheric pressure, and hourly cumulated precipitation. For all variables, except precipitation, the background (i.e. first guess) information is obtained by detrending the observations using the geographical parameters. For precipitation, the M. Lema radar-derived best estimate of precipitation rate at the ground is used. The characteristics of the OI schemes are shown in several test cases using data from ARPA Lombardia's mesoscale meteorological network. Finally, a quantitative diagnostics for temperature and relative humidity is carried out by using Cross Validation (CV) scores computed with large sets of data.
ARPA Lombardia (Italy): Operational maps (temperature, relative humidity) Lombardia is located in... more ARPA Lombardia (Italy): Operational maps (temperature, relative humidity) Lombardia is located in the southern side of the Alps. The grid box is 264 Km x 260 Km. The grey tones show the orography, with the Alps in the North, the Appennines in the South, and the Po Plain in ...
The predictability of convective systems is limited by the rapidly evolving non-hydrostatic dynam... more The predictability of convective systems is limited by the rapidly evolving non-hydrostatic dynamics and by the strong non-linearities present in moist thermodynamics, associated to convection processes. The perspective of the study is to assess the applicability of advanced data assimilation methods like AUS (Assimilation in the Unstable Subspace, Trevisan and Uboldi, 2006), but also 4D-Var or EnKF, which were successfully applied to larger scales.
In una relazione relativa a un lavoro svolto in precedenza (Uboldi, 2006) sono stati descritti al... more In una relazione relativa a un lavoro svolto in precedenza (Uboldi, 2006) sono stati descritti algoritmi, scelte di implementazione e applicazioni a casi di studio relativi a una procedura di interpolazione spaziale di misure di temperatura, che è attualmente disponibile per uso ...
Le osservazioni meteorologiche, e, più in generale, ambientali, in Lombardia costituiscono una re... more Le osservazioni meteorologiche, e, più in generale, ambientali, in Lombardia costituiscono una rete osservativa caratterizzata da una elevata risoluzione, se confrontata con quella dei dati GTS. La rete lombarda attuale, come quella di altre regioni italiane, risulta da un ...
Francesco Uboldi consulente e ricercatore indipendente e-mail, home. Interpolazione spaziale di o... more Francesco Uboldi consulente e ricercatore indipendente e-mail, home. Interpolazione spaziale di osservazioni meteorologiche da reti regionali ad alta risoluzione Agosto 2008...con qualche aggiornamento (2010) Introduzione ...
A hybrid scheme obtained by combining 3DVar with the Assimilation in the Unsta- ble Subspace (3DV... more A hybrid scheme obtained by combining 3DVar with the Assimilation in the Unsta- ble Subspace (3DVar-AUS) is tested in a QG model, under perfect model conditions, with a fixed observational network, with and without observational noise. The AUS scheme, originally formulated to assimilate adaptive observations, is used here to as- similate the fixed observations that are found in the region
The status of the work and the recent results of the application of the Assimilation in the Unsta... more The status of the work and the recent results of the application of the Assimilation in the Unstable Subspace are reported with special emphasis to the analysis of the stability induced by the assimilation of observations.
The ability of a data assimilation system to control the instabilities, present in the forecast e... more The ability of a data assimilation system to control the instabilities, present in the forecast error and responsible for error growth, can be improved by the combination of targeting strategies and dynamically consistent assimilation. The benefit of adaptively located observations is greatly enhanced if their positions and their assimilation are designed in order to target the instabilities, estimated by Breeding on the Data Assimilation System (BDAS). The analysis update has locally the same structure as the unstable structure whose maximum is in the location chosen for the adaptive observation. In this way, advantage can also be taken of an existing, fixed observational network, as long as this is is adequate to detect the migrating instabilities. These concepts are demonstrated by means of observing system simulation experiments with a quasi-geostrophic atmospheric model and with a primitive equation oceanic model.
Estimation of extreme event distributions and depth-duration-frequency (DDF) curves is achieved a... more Estimation of extreme event distributions and depth-duration-frequency (DDF) curves is achieved at any target site by repeated sampling among all available raingauge data in the surrounding area. The estimate is computed over a gridded domain in Northern Italy, using precipitation time series from 1929 to 2011, including data from historical analog stations and from the present-day automatic observational network. The presented local regionalisation naturally overcomes traditional station-point methods, with their demand of long historical series and their sensitivity to very rare events occurring at very few stations, possibly causing unrealistic spatial gradients in DDF relations. At the same time, the presented approach allows for spatial dependence, necessary in a geographical domain such as Lombardy, complex for both its topography and its climatology. The bootstrap technique enables evaluating uncertainty maps for all estimated parameters and for rainfall depths at assigned re...
In recent years, the use of mesoscale meteorological network data has been growing. An Optimal In... more In recent years, the use of mesoscale meteorological network data has been growing. An Optimal Interpolation (OI) method is used to interpolate on a regular grid the hourly averaged values of temperature, relative humidity, wind vector, atmospheric pressure, and hourly cumulated precipitation. For all variables, except precipitation, the background (i.e. first guess) information is obtained by detrending the observations using the geographical parameters. For precipitation, the M. Lema radar-derived best estimate of precipitation rate at the ground is used. The characteristics of the OI schemes are shown in several test cases using data from ARPA Lombardia's mesoscale meteorological network. Finally, a quantitative diagnostics for temperature and relative humidity is carried out by using Cross Validation (CV) scores computed with large sets of data.
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