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Abstract. Gross primary production (GPP) can be separated from flux tower measurements of net ecosystem exchange (NEE) of CO2. This is used increasingly to validate process-based simulators and remote-sensing-derived estimates of simulated GPP at various time steps. Proper validation includes the uncertainty associated with this separation. In this study, uncertainty assessment was done in a Bayesian framework. It was applied to data from the Speulderbos forest site, The Netherlands. We estimated the uncertainty in GPP at half-hourly time steps, using a non-rectangular hyperbola (NRH) model for its separation from the flux tower measurements. The NRH model provides a robust empirical relationship between radiation and GPP. It includes the degree of curvature of the light response curve, radiation and temperature. Parameters of the NRH model were fitted to the measured NEE data for every 10-day period during the growing season (April to October) in 2009. We defined the prior distribution of each NRH parameter and used Markov chain Monte Carlo (MCMC) simulation to estimate the uncertainty in the separated GPP from the posterior distribution at half-hourly time steps. This time series also allowed us to estimate the uncertainty at daily time steps. We compared the informative with the non-informative prior distributions of the NRH parameters and found that both choices produced similar posterior distributions of GPP. This will provide relevant and important information for the validation of process-based simulators in the future. Furthermore, the obtained posterior distributions of NEE and the NRH parameters are of interest for a range of applications.

Mangala field is one of the largest onshore oil fields in India. The Fatehgarh reservoirs consist of multi-Darcy permeability sandstones with low connate water saturations and moderate reservoir temperatures (62°ϾC). The reservoirs contain waxy and moderately viscous crude (9 -22 cP) resulting in adverse mobility ratio between oil and water. The field was originally developed using an inverted 9-spot, hot waterflood. Given the viscous nature of the oil, even before development of the field was initiated, it was envisaged that sweep improvement methods would have good potential to enhance overall recovery from the field. After detailed laboratory studies and a successful pilot, a full-field polymer flood has been implemented. Experience from the pilot highlighted the need for maintaining polymer solution integrity and ensuring good propagation of the flood; acquisition and analysis of reservoir surveillance data are crucial in order to implement a successful polymer flood.Initially, lab viscosity measurements of actual samples from the full-field project's injection lines conducted in aerobic conditions showed significantly lower values than what would be expected based on measurements made on polymer solutions in synthetic brine. Readings from an online viscometer, however, showed somewhat higher viscosities. Use of a stabilizer chemical during sample collection helped protect the sample from aerobic degredation, and the viscosity measurements more closely matched the online viscometer. The data re-emphasized the need to prevent oxygen from entering the system, and modificationsto the polymer preparation plant, Central Polymer Facility (CPF), to minimize oxygen ingress showed marked improvement in viscosity readings. This paper will detail the procedures followed to minimize the impact of oxygen (air) while taking samples and measuring viscosity.A detailed well and reservoir surveillance program was implemented at the start of polymer injection. Surveillance activities includedspinner surveys, fall-off tests, bottom-hole pressure measurements, and saturation monitoring. The paper also presents an analytical approach for the estimation of in-situ viscosity with fall-off surveys. These results are compared with modeled viscosity from simulation. All polymer injector wells were pre-produced for extended periods prior to start of polymer injection; previous experience showed that this improved injection (reduced skin) and conformance. The saturation monitoring survey and fall-off tests suggest good sweep and even re-saturation of oil in some sands. Integration of high resolution seismic data between injector-producer pairs and surveillance data helped the operator to take appropriate action on some under-performing producers which later showed significant improvement in performance.Initial oil production response from producers which are near to polymer injectors is encouraging, with significant increases in oil rate and decreases in water-cut. Samples collected from some of the producers show polymer breakthrough in...

A b s t r a c tThe REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tiesas farm in an agricultural area in the south of Spain. During the period of ten days, measurements were made to capture the main processes controlling the local and regional land-atmosphere exchanges. Apart from multi-temporal, multi-directional and multi-spatial space-borne and airborne observations, measurements of the local meteorology, energy fluxes, soil temperature profiles, soil moisture profiles, surface temperature, canopy structure as well as leaf-level measurements were carried out. Additional thermo-dynamical monitoring took place at selected sites. REFLEX 2012 CAMPAIGN 1467After presenting the different types of measurements, some examples are given to illustrate the potential of the observations made.