EOS Program Research Articles

MODIS and VIIRS Calibration History and Future Outlook

The MODIS is a key instrument for NASA’s EOS program, currently operated onboard the Terra and Aqua spacecraft launched in 1999 and 2002, respectively. The VIIRS is a MODIS follow-on instrument for the JPSS program. Adding to the ones operated onboard the S-NPP and NOAA-20 satellites launched in 2011 and 2017, respectively, three nearly identical VIIRS instruments will also be launched. This will enable the data records from MODIS and VIIRS to be extended beyond 2040. In addition to various applications and scientific studies of the Earth’s system, long-term data records from MODIS and VIIRS observations will greatly benefit the space-based climate observing system. This is attributed to the high-quality measurements and extensive calibration efforts, from pre-launch to post-launch. This paper provides an overview of MODIS and VIIRS calibration history and approaches applied to establish and maintain sensor calibration traceability and accuracy. It illustrates calibration and performance issues through different phases of the mission using examples derived from ground testing equipment, on-board calibrators, and other calibration targets. Moreover, discussed in this paper are outstanding challenges and future efforts to maintain and improve sensor calibration stability and long-term data quality, and to better support the space-based climate observing system.

Reduction of CO2 emissions of coal fired power plants by optimizing steam water cycle

Abstract To fulfill the energy demand now and in the next decades, coal-fired power plants will be an essential part of the portfolio of power plants that supply electricity cheaply and in a reliable way. The specific CO2 emissions of these plants can be reduced by increasing the efficiency. For that reason KEMA did optimize the steam water cycle of ultra super critical (USC) coal-fired power plants within the EOS program. The improvements are based on the application of the so-called Master Cycle, and on the application of higher steam temperatures. In the Master Cycle cold reheat steam is used in an extra turbine and with steam extraction of this turbine feed water preheating is realized with reduced exergy losses. The turbine is called a tuning turbine reflecting the improved possibilities to tune and optimize the steam cycle with the new coupling where the regenerative heater train and the re-heaters have been decoupled. The Master Cycle is proposed by Dong Energy . The first approach deals with the USC technology with a steam temperature of 600 °C and reheat temperatures of 620 °C. This technology is available at the moment and is applied in new built coal-fired power plants. The second approach deals with the USC technology with a steam temperature of 700 °C and reheat temperature of 720 °C. The expectation is that this technology can be applied around 2025 with the same availability as the USC units with 600 °C. The thermodynamic analyzes are carried out with KEMA’s flow sheeting package SPENCE®. In all considered cases the thermal input was 2400 MWth. In case of the application of the Master Cycle a second reheat is introduced. Results will be discussed and presented in tables, t-s diagrams and h-p diagrams. Improvement of efficiency of coal fired power station technology can reduce the amount of CO2 emitted significantly. This paper shows that with current available technology and improvements an additional emission reduction of almost 10% can be realised by applying the USC 700 + MC. Compared to the world wide average an emission reduction of 66% can be achieved without CCS. In the continuation of the analysis post combustion technology will be integrated in the concept to analyze possible additional benefits of the master cycle with respect to steam supply for the regeneration of the solvents.

The Sad Saga of Small Satellites

While the massive EOS program lumbers toward its first scheduled lauch in 1998, many global change variables are going unmonitored. So why not fill the gap with a separate program of simple, cheaper satellites to monitor such things as atmospheric aerosols, water vapor, clouds and the radiation budget Good idea, many NASA advisers have said. But a combination of NASA's reluctance and agency tug-of-wars seems likely to keep the small satellites grounded.

Global Change Fellowships awarded

After a detailed review process, 60 individuals were chosen to receive NASA Graduate Student Fellowships in Global Change Research for the 1991–92 academic year. The recipients represent 37 academic institutions from 23 states and 12 countries. The research topics of the new fellows fall into five basic categories: biogeochemical dynamics, climate and hydrological systems, ecological system and dynamics, and solid Earth processes.The Global Change Fellowship program was created to provide financial support for graduate students to pursue advanced degrees in the Earth sciences. The program trains a pool of scientists to help analyze and interpret the wealth of data generated during the Earth Observing System era. Initiated in 1990, the fellowship program was originally envisioned to scale up to fund 150 graduate students prior to the launch of the first EOS program, and to remain at that level during the life of the EOS mission. Due to the overwhelming response over its first two years, the program has already achieved 65% of this commitment.

EOS scrutinized again

NASA's plan for the Earth Observing System “simultaneously inspire[s] confidence and generate[s] concern,” according to a report released by the National Research Council's Space Studies Board on July 12. The report generally supports the EOS program's objectives and structure but questions its management. “EOS, as currently planned, will be the largest single component of the most ambitious scientific enterprise ever undertaken,” the board observed, and would require innovative and rigorous management. The board advocated developing EOS‐A “without delay” and supported the instruments proposed for EOS‐B, with the caveat that NASA evaluate the “optimum platform and orbit configuration7rdquo; for the second satellite.

Space Remote Sensors

Space remote sensors are analyzed as a component of a higher level ``robotic'' system and the implications for sensor parameter selection and priority assignment are described. The EOS program and three of its particular sensor types are considered as examples of the principles discussed.