Marine Primary Production (PP) is mostly based on the absorption of photosynthetically active radiation (PAR) by phytoplankton chlorophyll. The solar beams passing through the marine surface activate photosynthesis and the production of new living matter. In this work we evaluate the use of different sources of solar radiation for estimating PP in the Tuscany seas from 2005 to 2008. These sources comprise the solar radiation measured at some meteorological stations and the solar radiation estimated from satellite observations. The considered satellite products are the daily Surface Solar Irradiance (SSI), derived from the Ocean & Sea Ice Satellite Application Facility (O&SI SAF), and the PAR product of the SeaWiFS sensor, derived from the Ocean Color site of the National Aeronautics and Space Administration (NASA). A local model of PP has finally been fed with the PAR obtained from the two satellite products. The comparisons between the radiation data from the three sources show the slight superiority of the O&SI SAF over the SeaWiFS product. The former is in fact more consistent with the data taken at the weather stations, without showing the degradation patterns which are typical of land radiation measurements. The PP differences obtained by using the two PAR products are, however, marginal and limited to particular cases. The main features of the radiation sources examined are finally discussed in view of their possible utilization within an operational system for monitoring PP in the study area.
La Produzione Primaria (PP) marina si basa prevalentemente sull'assorbimento della radiazione fotosintetica attiva (PAR) da parte della clorofilla fitoplanctonica. I raggi solari attraversano la superficie marina, attivano la fotosintesi e la produzione primaria di nuova materia organica. In questo lavoro abbiamo valutato l'uso di differenti tipi di radiazione solare per la stima di PP nei mari della Toscana dal 2005 al 2008. Le tipologie di radiazione solare comprendono la radiazione misurata presso alcune stazioni meteorologiche e la radiazione stimata da osservazioni satellitari. I prodotti satellitari considerati sono i valori giornalieri di Surface Solar Irradiance (SSI), derivato dall'Ocean & Sea Ice Satellite Application Facility (O&SI SAF), e di PAR del sensore SeaWiFS, ottenuto dal sito Ocean Color della National Aeronautics and Space Administration (NASA). Un modello locale di PP è stato infine applicato con la PAR ottenuta dai due prodotti satellitari. Il confronto fra i tre tipi di radiazione mostra una debole superiorità del prodotto O&SI SAF rispetto al SeaWiFS. Il primo è, infatti, più coerente con i dati misurati nelle stazioni meteorologiche, senza mostrare i trend di degrado che sono tipici nelle misure radiometriche terrestri. Tuttavia, le differenze di PP ottenute usando i due tipi di prodotti PAR sono marginali e limitate a casi particolari. Infine, sono discusse le principali caratteristiche dei tipi di radiazione esaminati in vista di un loro possibile utilizzo all'interno di un sistema operativo per il monitoraggio della PP nell'area in studio.
La radiazione solare globale nei modelli di Produzione Primaria dei mari della Toscana
Maurizio Pieri;Piero Battista;Fabio Maselli;
2009
Abstract
Marine Primary Production (PP) is mostly based on the absorption of photosynthetically active radiation (PAR) by phytoplankton chlorophyll. The solar beams passing through the marine surface activate photosynthesis and the production of new living matter. In this work we evaluate the use of different sources of solar radiation for estimating PP in the Tuscany seas from 2005 to 2008. These sources comprise the solar radiation measured at some meteorological stations and the solar radiation estimated from satellite observations. The considered satellite products are the daily Surface Solar Irradiance (SSI), derived from the Ocean & Sea Ice Satellite Application Facility (O&SI SAF), and the PAR product of the SeaWiFS sensor, derived from the Ocean Color site of the National Aeronautics and Space Administration (NASA). A local model of PP has finally been fed with the PAR obtained from the two satellite products. The comparisons between the radiation data from the three sources show the slight superiority of the O&SI SAF over the SeaWiFS product. The former is in fact more consistent with the data taken at the weather stations, without showing the degradation patterns which are typical of land radiation measurements. The PP differences obtained by using the two PAR products are, however, marginal and limited to particular cases. The main features of the radiation sources examined are finally discussed in view of their possible utilization within an operational system for monitoring PP in the study area.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
