GESTIONE COMUNITARIA DEI TERRENI AGRICOLI: VALORIZZAZIONE DEL PATRIMONIO TERRITORIALE E SISTEMI ALIMENTARI LOCALI

The collective management of agricultural land, has its roots in the common goods of local communities, involving values and practices to greater social and territorial cohesion. In the urban-rural linkage, the “land” resource is a bridge between agriculture, sovereignty, finance and ecology; in this framework agroecology is the scientific and practical substrate for linking all the issues on agricultural land values. In this article we explore different practices that contributed at an unanimous consensus in the international community debate for recognizing in 2012 at FAO the rights on land tenure

ESPERIENZE DAL NORD E DAL SUD DEL MONDO VERSO LA CREAZIONE DI POLITICHE ALIMENTARI URBANE IN GRADO DI RENDERE PIU' SOSTENIBILI I SISTEMI ALIMENTARI DELLE CITTA'

Urban food policies are powerful institutional actions, to build more sustainable food systems of contemporary cities. These new policies are designed with a systemic and cross-sectoral approach, they able to act at the intersection of different issues and fields such as water, waste, planning, health, transport, education, environment, trade. We will describe the experiences developed in the Northern and Southern cities of the world (with a focus on West, Africa and Latin America), through the recent Milan Urban Food Policy Pact, which could start a new kind of city-to-city cooperation initiatives

Posicionamiento RT-NTRIP, una alternativa rápida y segura para la vinculación con los marcos de referencia

Desde el 2003 se vienen imponiendo las técnicas de posicionamiento a tiempo real (RT o Real Time) mediante el protocolo NTRIP (Networked Transport of RTCM −Radio Technical Commission for Maritime Services o Comisión Técnica de Radio para Servicios Marítimos− vía Internet Protocol), a través del cual son transmitidas correcciones diferenciales provenientes de estaciones del Global Navigation Satellite System (GNSS) Server-NTRIP, permitiendo a los usuarios posicionarse en tiempo real y de manera precisa. Una de las ventajas más relevantes de NTRIP es que permite obtener coordenadas referidas al marco de referencia de las estaciones Server-NTRIP de las que se reciben las correcciones, sin necesidad de realizar cálculos ni posprocesamiento. Antes de la aparición de las técnicas diferenciales a tiempo real, sólo se podía obtener precisión centimétrica realizando un procesamiento o cálculo diferencial con posterioridad al momento de la medición. Actualmente, con las técnicas RT se puede alcanzar dicha precisión en el instante de la medición y sin necesidad de tener amplios conocimientos geodésicos y del posicionamiento GNSS. Es por eso que estas técnicas están teniendo tanto auge, ya que permiten densificar los marcos de referencia en forma rápida, simple y segura

A Model for the Relationship between Rainfall, GNSS-Derived Integrated Water Vapour, and CAPE in the Eastern Central Andes

Atmospheric water vapour content is a key variable that controls the development of deep convective storms and rainfall extremes over the central Andes. Direct measurements of water vapour are challenging; however, recent developments in microwave processing allow the use of phase delays from L-band radar to measure the water vapour content throughout the atmosphere: Global Navigation Satellite System (GNSS)-based integrated water vapour (IWV) monitoring shows promising results to measure vertically integrated water vapour at high temporal resolutions. Previous works also identified convective available potential energy (CAPE) as a key climatic variable for the formation of deep convective storms and rainfall in the central Andes. Our analysis relies on GNSS data from the Argentine Continuous Satellite Monitoring Network, Red Argentina de Monitoreo Satelital Continuo (RAMSAC) network from 1999 to 2013. CAPE is derived from version 2.0 of the ECMWF’s (European Centre for Medium-Range Weather Forecasts) Re-Analysis (ERA-interim) and rainfall from the TRMM (Tropical Rainfall Measuring Mission) product. In this study, we first analyse the rainfall characteristics of two GNSS-IWV stations by comparing their complementary cumulative distribution function (CCDF). Second, we separately derive the relation between rainfall vs. CAPE and GNSS-IWV. Based on our distribution fitting analysis, we observe an exponential relation of rainfall to GNSS-IWV. In contrast, we report a power-law relationship between the daily mean value of rainfall and CAPE at the GNSS-IWV station locations in the eastern central Andes that is close to the theoretical relationship based on parcel theory. Third, we generate a joint regression model through a multivariable regression analysis using CAPE and GNSS-IWV to explain the contribution of both variables in the presence of each other to extreme rainfall during the austral summer season. We found that rainfall can be characterised with a higher statistical significance for higher rainfall quantiles, e.g., the 0.9 quantile based on goodness-of-fit criterion for quantile regression. We observed different contributions of CAPE and GNSS-IWV to rainfall for each station for the 0.9 quantile. Fourth, we identify the temporal relation between extreme rainfall (the 90th, 95th, and 99th percentiles) and both GNSS-IWV and CAPE at 6 h time steps. We observed an increase before the rainfall event and at the time of peak rainfall—both for GNSS-integrated water vapour and CAPE. We show higher values of CAPE and GNSS-IWV for higher rainfall percentiles (99th and 95th percentiles) compared to the 90th percentile at a 6-h temporal scale. Based on our correlation analyses and the dynamics of the time series, we show that both GNSS-IWV and CAPE had comparable magnitudes, and we argue to consider both climatic variables when investigating their effect on rainfall extremes

A Model for the Relationship between Rainfall, GNSS-Derived Integrated Water Vapour, and CAPE in the Eastern Central Andes

Atmospheric water vapour content is a key variable that controls the development of deep convective storms and rainfall extremes over the central Andes. Direct measurements of water vapour are challenging; however, recent developments in microwave processing allow the use of phase delays from L-band radar to measure the water vapour content throughout the atmosphere: Global Navigation Satellite System (GNSS)-based integrated water vapour (IWV) monitoring shows promising results to measure vertically integrated water vapour at high temporal resolutions. Previous works also identified convective available potential energy (CAPE) as a key climatic variable for the formation of deep convective storms and rainfall in the central Andes. Our analysis relies on GNSS data from the Argentine Continuous Satellite Monitoring Network, Red Argentina de Monitoreo Satelital Continuo (RAMSAC) network from 1999 to 2013. CAPE is derived from version 2.0 of the ECMWF’s (European Centre for Medium-Range Weather Forecasts) Re-Analysis (ERA-interim) and rainfall from the TRMM (Tropical Rainfall Measuring Mission) product. In this study, we first analyse the rainfall characteristics of two GNSS-IWV stations by comparing their complementary cumulative distribution function (CCDF). Second, we separately derive the relation between rainfall vs. CAPE and GNSS-IWV. Based on our distribution fitting analysis, we observe an exponential relation of rainfall to GNSS-IWV. In contrast, we report a power-law relationship between the daily mean value of rainfall and CAPE at the GNSS-IWV station locations in the eastern central Andes that is close to the theoretical relationship based on parcel theory. Third, we generate a joint regression model through a multivariable regression analysis using CAPE and GNSS-IWV to explain the contribution of both variables in the presence of each other to extreme rainfall during the austral summer season. We found that rainfall can be characterised with a higher statistical significance for higher rainfall quantiles, e.g., the 0.9 quantile based on goodness-of-fit criterion for quantile regression. We observed different contributions of CAPE and GNSS-IWV to rainfall for each station for the 0.9 quantile. Fourth, we identify the temporal relation between extreme rainfall (the 90th, 95th, and 99th percentiles) and both GNSS-IWV and CAPE at 6 h time steps. We observed an increase before the rainfall event and at the time of peak rainfall—both for GNSS-integrated water vapour and CAPE. We show higher values of CAPE and GNSS-IWV for higher rainfall percentiles (99th and 95th percentiles) compared to the 90th percentile at a 6-h temporal scale. Based on our correlation analyses and the dynamics of the time series, we show that both GNSS-IWV and CAPE had comparable magnitudes, and we argue to consider both climatic variables when investigating their effect on rainfall extremes.Fil: Ziarani, Maryam Ramezani. Universitat Potsdam; Alemania. German Research Centre for Geosciences; AlemaniaFil: Bookhagen, Bodo. Universitat Potsdam; AlemaniaFil: Schmidt, Torsten. German Research Centre for Geosciences; AlemaniaFil: Wickert, Jens. German Research Centre for Geosciences; Alemania. Technishe Universitat Berlin; AlemaniaFil: de la Torre, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Austral; ArgentinaFil: Deng, Zhiguo. German Research Centre for Geosciences; AlemaniaFil: Calori, Andrea Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; Argentin

Comparison between GNSS ground-based and GPS radio occultation precipitable water observations over ocean-dominated regions

Precipitable water (PW) inferred from GPS (Global Positioning System) radio occultation (RO) and ground-based (GB) Global Navigation Satellite System (GNSS) observations are compared between years 2007 and 2014. As previous studies were mainly performed over continental areas we now focus over ocean-dominated geographical areas. Our analysis is done in order to find out how the reliability level of RO results over oceanic areas compares to land. As RO soundings usually miss some information close to the ground, we also assess different methods to complete the lacking data. We found 47 terrestrial stations that lie in islands small and far away from continental areas where the weather might be governed by the sea conditions. From comparisons of almost 5000 collocated samples, PW from RO and GB exhibit a global mean difference around 1 mm, root-mean-square deviation about 5 mm and a correlation above 0.9. The 2007–2014 timeseries and the monthly mean RO and GB PW were also compared to reanalyses per hemisphere, latitude regions and oceans. In each zone it was found that PW from RO, GB and reanalyses all exhibit in general consistent seasonal qualitative behavior. However, quantitative differences exist between reanalyses on one side and RO and GB on the other side. It is shown that PW from reanalyses lacks reliability in areas where the island topography is poorly represented by them. We also conclude that RO and GB seem to be more sensitive for the detection of features that depart from the regular annual cycle.Fil: Burgos Fonseca, Yuditsabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Alexander, Pedro Manfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: de la Torre, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Austral. Facultad de Ingeniería; ArgentinaFil: Hierro, Rodrigo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Austral. Facultad de Ingeniería; ArgentinaFil: Llamedo Soria, Pablo Martin. Universidad Austral. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Calori, Andrea Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ingeniería; Argentin

SIRGAS-CON una red geodésica utilizada en el monitoreo del vapor de agua troposférico sobre Latinoamérica

El sistema Tierra se encuentra en permanente estudio. Diversas ciencias analizan variables específicas que requieren su georreferenciación. La variación del nivel del mar, la tectónica, el monitoreo atmosférico, son ejemplos evidentes de esta necesidad. Se evidencia la demanda de un marco de referencia único, preciso y global. Este ha sido definido por la Unión Internacional de Geodestas y Geofísicos, es el ITRF. En América Latina se materializa, mediante una suma de esfuerzos colaborativos en la red SIRGAS_CON. Con el objeto de optimizar el aprovechamiento de esta red, se ha trabajado en definir, aplicar y validar una metodología que permita el cálculo indirecto del Vapor de Agua Troposférico. Se han presentado avances sobre el marco teórico, la metodología aplicada y la validación del método, sobre la base de la subred SIRGAS-CON-D_SUR procesada por el centro de procesamiento de Mendoza, CIMA. En este trabajo se presentan los avances logrados en los últimos dos años sobre la inclusión y ajuste de los retardos troposféricos estimados por distintos centros de procesamiento, abarcando la totalidad de las estaciones continuas SIRGAS operativas

Monitoreo a tiempo real del contenido de vapor de agua en la troposfera a partir de observaciones GNSS en Latinoamérica

Definir y aplicar una metodología que permita monitorear el Vapor de Agua Troposférico a tiempo real, en los distintos sitios donde se dispone de una estación GNSS continua online en la región, realizando un aporte significativo a las ciencias Atmosféricas

Monitorización del contenido de vapor de agua en la tropósfera a partir de las observaciones GPS en Latinoamérica

La Tierra es un sistema complejo en el que convergen gran cantidad de variables. El agua ocupa un rol fundamental en el desarrollo de la vida. En su estado gaseoso, el vapor de agua atmosférico, es objeto de constante estudio. Es el gas más abundante del efecto invernadero. Sin él la temperatura en la superficie del planeta estaría muy por debajo del punto de congelación. Los cambios de fase, la condensación y la evaporación, involucran a los intercambios de energía de calor latente, que afectan a la estabilidad vertical de la atmósfera, a la estructura, a la evolución de sistemas de tormenta, y al balance energético del sistema climático mundial (Chahine, 1992). Un mayor conocimiento del contenido de vapor de agua troposférico permitiría una mejor comprensión de los procesos atmosféricos, facilitando así también la previsión meteorológica. Sin embargo la mayor dificultad que presenta la comprensión de la distribución de vapor de agua se debe principalmente a su propia complejidad, tanto de movimiento como de transporte a lo largo de la atmósfera, resultando en una variable altamente cambiante en el tiempo y en el espacio. El conocimiento de esta variable requiere de una medición permanente y en lo posible a partir de una amplia red de observación que asegure su monitorización espacial