With the exception of satellites at both ends of the spectrum, environmental satellites usually have a lifespan of only a few years. On the other hand, launching a new satellite requires a planning period of about 10 years. Therefore, the new satellite technology in orbit is relatively lagging behind. We are in a transitional period between the old and new generations of observing systems. In the next few years, the international satellite constellation will achieve significant improvements in various aspects, such as space, spectrum, time, and radiometric resolution. The following will focus on the development of the next generation of satellites in the next 10 years, especially the development of solar energy forecasting.
NOAA’s Sun Synchronous Satellite Constellation (POES) is equipped with an Advanced Very High Resolution Radiometer (AVHRR). In the process of cooperation with NASA, NOAA is transforming its satellite system into the Joint Polar Satellite System (JPSS), which is located in the transit orbit in the afternoon (13:30) and is equipped with a 22-band visible light/infrared imager. /Radiometer Kit (VIRS). By using the research-grade medium-resolution imaging spectroradiometer (MODIS) provided by NASA, VIRS has a variety of spatial and spectral capabilities. The Misso National Polar Orbiting Partnership Satellite (Suomi NPP) launched by the United States in October 2011 can reduce the operational risk of JPSS. The polar project organized by EμmETSAT is complementary to JPSS, whose meteorological operation (MetOp) satellite is located in the transit orbit in the morning (09:30). In the orbit near the twilight circle (06:00 am local time), the linear scanning system (OLS) carried by the National Defense Meteorological Satellite (DMSP) further improves the polar satellite data. Table 3.1 shows the spectrum kit of these optical sensors (please note that MetOp is equipped with an AVHRR sensor). By 2020, the meteorological satellite MetOp project will transition to the Post-EμmETSAT Polar System (Post-EPS), and carry METImage sensors with similar performance to VIIRS. The next-generation national defense weather satellite system is also under study. After implementation, the system can assist existing polar orbiting satellites and provide an ideal update frequency.
Geostationary satellites will also be equipped with advanced remote sensing technology in the next few years. The second-generation European meteorological satellite is equipped with a 12-band scanning enhanced visible light and infrared imager (SEVIRI), in the existing standard GOES 5-channel package (visible light, near-infrared, water vapor and two thermal infrared near 11μm Major progress has been made on the basis of window frequency bands. In 2014, the Japanese Space Agency launched the first Sunflower series satellite equipped with an Advanced Baseline Imager (ABI). The performance of the ABI is comparable to the next-generation GOES-R series satellites scheduled to be launched in 2017. The current GOES imager is updated every 30 minutes in Europe and can provide global images every 3 hours, while the AB1 only needs 5 minutes and 15 minutes to complete the same coverage effect. In addition to improving the spectral and temporal resolution, the spatial resolution of visible light will increase from 1km to 0.5km, and the spatial resolution of infrared will increase from 4km to 2km.
According to this trend, the third-generation meteorological satellite system (MTG), like the Post-EPS polar system, will be put into use in 2020. The third-generation meteorological satellite system will be equipped with a “flexible combined imager” (FCI) 16-band radiometer and a dedicated platform for atmospheric detection, which can be used to estimate temperature, humidity profile and cloud top height. Countries such as Canada, Russia, China, South Korea, India, and Brazil have completed or are about to complete environmental satellite projects that complement the Global Earth Observation System.
The role of imaging radiometers in solar applications. It can be seen from the definition that this kind of passive||observing system can collect reflected radiation as well as emitted radiation, which is completely different from an active||system that first emits and then receives radiation. For example, radar and lidar are active systems. Although these sensors are rarely used on space observation platforms, they are gradually appearing in space applications. In addition, their ability to observe clouds and aerosols is also worth mentioning. Currently well-known systems include: NASA’s cloud detection satellite CloudSat and cloud aerosol lidar and infrared pathfinder satellite observation system Scientific Pathfinder Program (ESSP). The 94GHz radar carried by CloudSat can perform meteorological cloud performance analysis at a vertical resolution of 240m, and the 532nm (main) lidar carried by CALIPSO can perform aerosol performance analysis at a resolution of 30m. These sensors are highly complementary in the sensitivity of clouds, aerosols and precipitation. The NASA “A-Train” constellation sensor flying in the 1330 sun-synchronous orbit, together with the sensors of Aqua-MODIS and several other satellites, provides a powerful test platform for the next generation of cloud and aerosol remote sensing operations.
Both CloudSat and CALIPSO are equipped with non-scanning sensors in the nadir observation mode, so they can only provide a cross-section through the atmosphere along the ground track (or “curtain observation”). Recently, researchers including Barker et al. and Miller et al. have attempted to establish the three-dimensional distribution of clouds through active/passive coordinated observations of A-Train satellite formations, and correlate curtain observations with local cloud areas. Although the coverage of the active system is limited, it can provide key information that some passive systems cannot provide. Figure 1 shows the internal structure information in detail. Currently, the European Space Agency (ESA) plans to launch the EathCARE satellite in 2016. The application of these active systems in the near future will improve our understanding of the physical processes of the cloud layer and its attributes in the NWP model. In the next few decades, satellites equipped with scanning active sensors will completely describe the three-dimensional structure of aerosol and water vapor condensate distribution for the first time, and then establish new NWP analysis paradigms and cloud and aerosol prediction capabilities.