Hyperspectral thermal infrared sounders enable us to grasp the global behavior of minor atmospheric constituents. Ammonia, which imparts large impacts on the atmospheric environment by reacting with ...other species, is one of them. In this work, we present an ammonia retrieval system that we developed for the Greenhouse Gases Observing Satellite (GOSAT) and the estimates of global atmospheric ammonia column amounts that we derived from 2009 to 2014. The horizontal distributions of the seasonal ammonia column amounts represent significantly high values stemming from six anthropogenic emission source areas and four biomass burning ones. The monthly mean time series of these sites were investigated, and their seasonality was clearly revealed. A comparison with the Infrared Atmospheric Sounding Interferometer (IASI) ammonia product showed good agreement spatially and seasonally, though there are some differences in detail. The values from GOSAT tend to be slightly larger than those from IASI for low concentrations, especially in spring and summer. On the other hand, they are lower for particularly high concentrations during summer, such as eastern China and northern India. In addition, the largest differences were observed in central Africa. These differences seem to stem from the temporal gaps in observations and the fundamental differences in the retrieval systems.
Dust aerosols, which have diverse and strong influences on the environment, must be monitored. Satellite data are effective for monitoring atmospheric conditions globally. In this work, the modified ...CO₂ slicing method, a cloud detection technique using thermal infrared data from space, was applied to GOSAT data to detect the dust aerosol layer height. The results were compared using lidar measurements. Comparison of horizontal distributions found for northern Africa during summer revealed that both the relative frequencies of the low level aerosol layer from the slicing method and the dust frequencies of CALIPSO are high in northern coastal areas. Comparisons of detected layer top heights using collocated data with CALIPSO and ground-based lidar consistently showed high detection frequencies of the lower level aerosol layer, although the slicing method sometimes produces overestimates. This tendency is significant over land. The main causes of this tendency might be uncertainty of the surface skin temperature and a temperature inversion layer in the atmosphere. The results revealed that obtaining the detailed behavior of dust aerosols using the modified slicing method alone is difficult.
Although wetlands are the largest natural source of atmospheric methane, the amount and variability of methane emissions from wetlands still have large uncertainty. We investigated the local growth ...rate of the column-averaged methane dry air mole fraction (XCH4) in Siberia where wetlands are widely abundant using 11-year (2009-2019) Greenhouse gases Observing SATellite (GOSAT) data. While the mean growth rate during the summer from the GOSAT observations is 7.2 ppb yr−1 globally, that in West Siberia is 8.4 ppb yr−1. In particular, the growth rates in West Siberia after 2013 is much larger in July and August than in the other months. Moreover, the growth of XCH4 in West Siberia appears to larger than in the other boreal areas. These results imply that methane emissions from wetlands in West Siberia increased during the summer in recent several years.
The Greenhouse gases Observing SATellite 2 (GOSAT-2) was launched in October 2018 as a successor to GOSAT (launched in 2009), the first satellite to specialize in greenhouse gas observations. ...Compared to the GOSAT sensors, the sensors of GOSAT-2 offer higher performance in most respects. The quality and quantity of data from observations are expected to be improved accordingly. The signal-to-noise ratio (SNR) is better in both the SWIR and TIR bands of TANSO-FTS-2, which is the main sensor of GOSAT-2. This improvement ultimately enhances the accuracy of greenhouse gas concentration analysis. Furthermore, because of the improved SNR in the SWIR band, the northern limit at which data are obtainable in high-latitude regions of the Northern Hemisphere in winter, where observation data have remained unavailable because of weak signal strength, has moved to higher latitudes. As better data are obtained in greater quantities, progress in carbon cycle research for high-latitude regions is anticipated. Moreover, the improvement of SNR in the TIR band is expected to be considerable. Particularly, the resolutions of the vertical concentration distributions of CO
2
and CH
4
have been improved drastically. The first function introduced for GOSAT-2 that is not in GOSAT is an intelligent pointing mechanism: a cloud area avoidance function using the in-field camera of TANSO-FTS-2. This function can increase the amounts of observation data globally and can improve the accuracy of CO
2
emissions estimation and measurements of uptake intensity. The effects are expected to be strong, especially for the tropics because cumulus clouds are the most common cloud type. The intelligent pointing system can avoid the clouds effectively. Another important benefit of TANSO-FTS-2 is that the wavelength range of Band 3 of SWIR has been expanded for measuring carbon monoxide (CO). Because CO originates from combustion, it is used to evaluate some effects of human activities in urban areas and biomass burning in fields. Particularly, black carbon-type aerosols can be measured by the sub-sensor, TANSO-CAI-2, to assess biomass burning along with CO
2
and CO by TANSO-FTS-2.
Abstract
The short-wavelength infrared bands of the Thermal and Near-Infrared Sensor for Carbon Observation (TANSO)–Fourier transform spectrometer (FTS) instrument on board the
Greenhouse Gas ...Observing Satellite
(
GOSAT
) have degraded, which affects the retrieval of data for CO
2
and CH
4
. Herein, a new algorithm that uses principal component analysis (PCA) to evaluate these degradations from on-orbit solar calibration spectra has been developed. The datasets of the spectra were decomposed using PCA, and the temporal variations of their components were fitted using the appropriate functions. Our results show that PCA is effective to construct a suitable degradation model for TANSO-FTS. Comparisons of CO
2
data retrieved using the new degradation model with that using the ground-based FTS indicate that the new model improves the measurement biases.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Column-averaged dry air mole fractions of carbon dioxide and methane (XCO2 and XCH4) retrieved from SWIR (Short-Wavelength InfraRed) observations by GOSAT (Greenhouse Gases Observing SATellite) since ...2009 and its successor GOSAT-2 since 2019 are available from NIES (National Institute for Environmental Studies) as SWIR L2 (Level 2) products. This paper shows the current status of the data quality of NIES SWIR L2 products and inter-satellite comparison results. Comparisons of XCO2 and XCH4 obtained from each satellite with ground-based observations from the TCCON (Total Carbon Column Observing Network) reveal that the averaged single measurement precision are less than 1.9 ppm and 10 ppb, respectively, and the site-to-site biases are less than 0.9 ppm and 5 ppb, respectively. The standard deviations of the inter-satellite differences for XCO2 and XCH4 are 2.18 ppm and 12.1 ppb, respectively, on an individual-data basis and 1.77 ppm and 11.7 ppb, respectively, on a monthly-regional-mean basis. While further improvements in the retrieval algorithm and bias-correction method are needed, GOSAT and GOSAT-2 retrievals are generally in good agreement.
Display omitted
•Emulsions of long-chain amidoamine derivatives (CnAA) can induce thermal color changes.•The effect of the alkyl chain length of CnAA on the coloring behavior and temperature range ...was investigated.•The change in the alkyl chain length affected only the coloring temperature but not the coloring behavior.•The coloring-temperature range was able to adjust precisely using mixtures of CnAAs with different alkyl chains.
Structurally colored materials that respond to external stimuli have attracted considerable attention as emerging colors. Structurally colored materials are mainly based on periodic arrays of solids; however, all-liquid colored materials with variable shapes are rare. We previously reported that all-liquid emulsions composed of a long-chain amidoamine derivative (CnAA; n = 18) and tetraoctylammonium bromide develop structural color in a narrow temperature range and that temperature can induce color changes. However, the adjustable temperature range for coloration is narrow, and coloration at high temperatures was not achievable. In this study, we investigated the effect of alkyl chain length of CnAA on coloring behavior and temperature range, and demonstrated that coloring-temperature range can be considerably increased (up to ∼65 °C) by shortening the chain length. The advantage of thermally induced color change is retained by changing the chain length. For any CnAA, the color is blue-shifted upon heating to higher temperatures, and color tone is tunable via CnAA concentration. Furthermore, mixing CnAAs with different chain lengths is effective in adjusting the coloring temperature, allowing precise control of the coloring temperature according to the mixing ratio.
The Global Observation SATellite for Greenhouse gases and Water cycle (GOSAT-GW) is planned to be launched in FY2024. Total Anthropogenic and Natural emissions mapping SpectrOmeter-3 (TANSO-3) on ...GOSAT-GW has three bands in the range from visible to shortwave infrared spectral regions, including the carbon dioxide (CO2) and methane (CH4) absorption bands. The GOSAT-GW project will provide column-averaged dry air mole fractions of CO2 and CH4 (XCO2 and XCH4, respectively) estimated from the observed spectra as the TANSO-3 Level 2 greenhouse gas (L2GHG) product. This product is processed by the algorithm called GOsat Retrieval ALgorithm (GORAL), which includes two different greenhouse retrieval techniques; the full physics and proxy methods. The full physics method simultaneously estimates XCO2 and XCH4 with explicit consideration of multiple scattering by aerosols in the radiative transfer calculations. The proxy method estimates XCH4 utilizing CO2 as a proxy to resolve contamination by multiple scattering using the close absorption bands of CO2 and CH4 near 1.6 μm.
In recent years, various tactile displays having the ability to change their surface friction have been proposed. These displays can express many types of textures and shapes that the materials used ...for them do not possess. In our study, we found that the ultrasound converged on the surface of polystyrene foam reduces the surface friction. This method has potential applications in disposable and three-dimensional tactile displays. In this study, physical and psychophysical experiments were conducted to verify the effectiveness of the proposed method and to examine the basic conditions under which it is perceived. As a result, we confirmed that the surface friction was reduced on the polystyrene foam, which may be due to the squeeze film effect caused by the external ultrasound excitation of the surface.
PDF
