2021-05-17

NASA’s solar multi-wavelength data provides sufficient research data for climate models

By yqqlm yqqlm

NASA’s solar multi-wavelength data provides sufficient research data for climate models

The sun is the power source of the earth. It uses visible light and ultraviolet radiation Energy is emitted in the form of (shorter wavelength) and near-infrared radiation (longer wavelength, what we feel is heat). Visible light reflects off light-colored surfaces such as snow and ice, while dark surfaces such as forests or oceans absorb it. This kind of reflectivity is called albedo. It is a key way for the earth to adjust its temperature. If the earth absorbs more energy than it reflects, it will become warmer. If it reflects more energy than it absorbs, it will become warmer. cold.

When scientists mix in the influence of other wavelengths, the situation becomes more complicated. In the near-infrared part of the spectrum, surfaces like ice and snow are non-reflective–in fact, the way they absorb near-infrared light is very similar to the way that dark T-shirts absorb visible light.

“People think snow reflects light. It is so shiny,” Gavin Shi, director of NASA’s Goddard Institute for Space Research in New York City and NASA’s acting senior climate consultant Mitt said. “But it turns out that in the near-infrared part of the spectrum, it can almost be seen as black.”

Obviously, for climate scientists, it is necessary to obtain a complete picture of how solar energy enters and leaves the earth system , They need to include wavelengths other than visible light.

The earth’s energy budget is a metaphor for the delicate balance between the energy received from the sun and the energy radiated back into space. The study of the precise details of the Earth’s energy budget is critical to understanding how the Earth’s climate changes and solar energy output changes. This is where NASA’s Total Solar Irradiance and Spectral Sensor (TSIS-1) comes into play. From a vantage point on the International Space Station, TSIS-1 not only measures the total solar irradiance (energy) reaching the Earth’s atmosphere, but also measures the energy of each wavelength. This measurement is called Spectral Solar Irradiance, or SSI. The TSIS-1 Spectral Irradiance Monitor (SIM) was developed by the Atmospheric and Space Physics Laboratory of the University of Colorado Boulder. The accuracy of measuring SSI is better than 0.2%, or within 99.8% of the true SSI value.

“With TSIS-1, we have greater confidence in the measurement of visible and near-infrared light,” said Dr. Xianglei Huang, a professor in the Department of Climate and Space Science and Engineering at the University of Michigan. “How do you divide the energy of each wavelength has an impact on the average climate.”

The composition of light falling on the earth is important for understanding the energy budget of the earth. NASA’s Total Solar and Spectral Irradiance Sensor (TSIS-1) measures the energy of the sun at 1,000 different wavelengths, including visible light, ultraviolet and infrared, and is called solar spectral irradiance. Huang and his colleagues at the University of Michigan, NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Colorado Boulder recently used TSIS-1 SSI data for the first time in a global climate model. Dong Wu, a TSIS-1 project scientist at Goddard, said: “In the past, several studies have used various SSI inputs to analyze the sensitivity of climate models.” However, this study is the first to investigate how new data changes the poles of the earth. Solar reflection and absorption model.

They found that when they used the new data, the model showed a statistically significant difference in how much energy the ice and water absorb and reflect compared to using the old solar data. The team ran a model called the Community Earth System Model (CESM2) twice: once using new data from TSIS-1 averaged over an 18-month period, and another time using data from the Solar Radiation and Climate Experiment (SORCE) based on NASA’s decommissioning The old, reconstructed average.

The research team found that compared with the old SORCE reconstruction data, the TSIS-1 data has more energy in the visible wavelengths and less energy in the near-infrared wavelengths. These differences mean that in the operation of TSIS-1, the sea ice absorbs less energy and reflects more energy, so the polar temperature decreases by 0.5 to 1.3 degrees Fahrenheit, and the summer sea ice cover can increase by about 2.5%.

“We want to know how the new observations compare with the observations used in previous model studies, and how this affects our perception of climate,” said lead author Dr. Xianwen Jing, who serves as the University of Michigan Postdoctoral scholars in the Department of Climate and Space Science and Engineering conducted this research. “If there is more energy in the visible light band and less energy in the near-infrared band, this will affect the amount of energy absorbed by the surface. This can affect the growth or contraction of sea ice, and the degree of coldness in high latitudes.”

This tells us that in addition to monitoring the total solar irradiance, we also need to pay close attention to the spectrum. Although more accurate SSI information will not change the overall picture of climate change, it may help modelers better simulate how different wavelengths of energy affect climate processes, such as ice behavior and atmospheric chemistry.

The author warns that even if the new data makes the polar climate look different, there are still more steps to be done before scientists can use it to predict future climate change. The team’s next steps include investigating how TSIS data affects models in low-latitude regions, and continuing to observe in the future to observe changes in SSI throughout the solar cycle.

Learning more about how all the wavelengths of sunlight interact with the Earth’s surface and systems will provide scientists with more and better information to simulate the current and future climate. With the help of TSIS-1 and its successor TSIS-2 (which will be launched on NASA’s own spacecraft in 2023), NASA is achieving an explanation of the energy balance of the Earth and how it changes.