High resolution micro-spectrometers (~1 nm) (Space Exploration part)
ECG team’s future plan is to collect more datasets from a space based micro-spectrometer with improved characteristics such as higher spectral resolution and sensitivity. Improved spectral resolution and higher sensitivity of the space instrument will reduce the amount of the noisy datasets and enable us to distinct individual lines due to greenhouse gases, particulate matters PM2.5 and combustion-originated aerosol pollutions. The proposed latest generation of the miniaturized space micro-spectrometers retain all important characteristics such as low cost, small-size and small weight. These micro-spectrometers are environment friendly as after completion of their space missions they can be entirely burned up in the Earth stratosphere preventing falling hazardous debris on the ground.
Spectrally Integrated Voigt Function
In 1992 Brüggemann and Bollig introduced the integrated Voigt function and its mathematical and computational aspects [Brüggemann and Bollig, JQSRT 48 (1) (1992) 111-114]. Members of our team first proposed how the integrated Voigt function can be effectively implemented practically as the Spectrally Integrated Voigt Function (SIVF) in line-by-line radiative transfer computation as a new promising technique as an alternative to the traditional Voigt function to compute absorption coefficients of the molecular gases by using spectroscopic molecular database HITRAN. Mathematically, the SIVF method represents the mean value of the integrated Voigt function that accounts for the area under the Voigt function within given subinterval. Consequently, this method retains information even at reduced spectral resolution. The reduced spectral resolution enables us to apply the sparse grid‑points to accelerate computation without loss of accuracy. More detailed information about SIVF and its application can be found in our publication [Quine & Abrarov, JQSRT, 127 (2013) 37-48]. It is interesting to note that recently Ilakovac reported that the integrated Voigt function can also be used for efficient calculation of the peak shapes [Ilakovac, Acta Phys. Polonica A,136 (1) (2019) 107-113].
A method for carbon dioxide detection
ECG team member with coauthor proposed first to use a new method for determination of mixing ratio of CO2 within a small spectral range from 1550 to 1600 nm. The advantage of this method is no overlap with lines contributed from all other greenhouse gases. This method ensures that because of no overlap the concentration of carbon dioxide CO2 can be determined more reliably as only this gas contributes to the spectral radiation within this specific spectral band.
New methodologies in detection of fires (Albedo)
Radiance Enhancement (RE) is a new method that was proposed by one of our ECG team members for efficient detection of cloud scenes by NIR radiance data from space micro-spectrometer. Recently is has been found that RE method can also be very promising for detection and monitor the level of smoke-originated aerosols. Therefore, this method can also be used to detect forest fires or fires on the fields after harvesting. These fires deteriorate the quality of the breezing air especially over the urban areas and large cities where the pollutants tend to accumulate. The deteriorated air due to smoke can cause many respiratory and blood system diseases. The RE method can also be used for efficient location of fires sources over forests and rural areas.
2D imaging in NIR (Space Ecploaration)
As a future plan we also consider a possibility to launch a cluster of space based micro-spectrometers that can be capable to produce the spectral data for 2D near infrared (NIR) imaging. This innovative idea has been also first proposed by ECG team member.
Software development (Mathematical Method Section)
With available datasets ECG team performs numerical correlations based on statistical analysis. We can correlate the statistical data obtained from North America on the Western Hemisphere and Asian countries on the Eastern hemisphere. Such a correlation is required for prediction of the local dynamics of pollutants and greenhouse gases. These datasets can also be used to develop new methods and algorithms in observation of surface Albedo over ground, Oceans and Seas. The Radiance Enhancement (RE) method proposed by member of ECG can be used to detect cloud scenes. Recently it has been found that the RE method can also be efficient for smoke-originated aerosols appearing as a result of fires on the ground. All these methods are coded as library function files for line-by-line computation in radiative transfer applications.