Global development has been heavily reliant on the overexploitation of natural resources since the Industrial Revolution. With the extensive use of fossil fuels, deforestation, and other forms of land-use change, anthropogenic activities have contributed to the ever-increasing concentrations of greenhouse gases (GHGs) in the atmosphere, causing global climate change. In response to the worsening global climate change, achieving carbon neutrality by 2050 is the most pressing task on the planet. To this end, it is of utmost importance and a significant challenge to reform the current production systems to reduce GHG emissions and promote the capture of CO 2 from the atmosphere. Herein, we review innovative technologies that offer solutions achieving carbon (C) neutrality and sustainable development, including those for renewable energy production, food system transformation, waste valorization, C sink conservation, and C-negative manufacturing. The wealth of knowledge disseminated in this review could inspire the global community and drive the further development of innovative technologies to mitigate climate change and sustainably support human activities.

[1] We adopt a broad spectral data analyzing method to derive the continuous altitude variability of inertial gravity wave (GW) parameter properties in the altitude range of 2-25 km from 11 year (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008) radiosonde observations over 92 United States stations locating in the latitude range from 5°N to 75°N. To our knowledge, this is the first time presenting latitudinal and continuous altitudinal variability of lower atmospheric GW parameters. The presented latitudinal distribution of GW parameters indicates that the wave energy in the troposphere and lower stratosphere peaks, respectively, at the middle and lower latitudes; and at lower latitudes, GWs usually have larger ratios of wave intrinsic frequency to Coriolis parameter, smaller intrinsic frequencies, shorter vertical wavelengths, and longer horizontal wavelengths. Our analyses also revealed continuous altitudinal variations of GW parameters, most of which are closely related to those of the background temperature and wind fields, indicating the important role of background atmosphere in excitation and propagation of GWs. Moreover, our results suggested the profound climatological impacts of GWs on background atmosphere. The GW-induced force tends to decelerate the zonal jet at middle latitudes and produces a negative vertical shear in the northward wind closely above the tropopause altitude. The GW heat flux tends to cool the atmosphere around the tropospheric jet altitude and contributes significantly to the forming of tropospheric inversions at middle latitudes. Additionally, we demonstrated that GW energy densities, momentum, and heat fluxes have evident seasonal variations, especially at middle latitudes.

[1] An observational study of nonlinear interaction between the quasi 2 day wave (QTDW) and the diurnal and semidiurnal tides from meteor radar measurements at Maui is reported. The diurnal and semidiurnal tides show a short-term variation with the QTDW activity. The variation of amplitude of the semidiurnal tide is opposite to that of the QTDW. The minimum amplitudes of the diurnal tide appear several days later than the maximum amplitudes of the QTDW, and the diurnal tide obviously strengthens when the QTDW drops to small amplitudes. The bispectrum analysis shows significant nonlinear interactions among the QDTW and the tidal components. The two quasi 16 h modes with periods of 16.2 h and 15.8 h generated in the interactions of the QTDW with the diurnal and semidiurnal tides can clearly be distinguished because of the slight deviation of the QTDW period from 48 h. The bicoherence spectrum demonstrates that the QTDW and the semidiurnal tide have quite strong levels of coherence, indicating that the nonlinear interaction is a mechanism responsible for the variability of the semidiurnal tide. Although there is also some interaction between the QTDW and the diurnal tide, their coherence level is low. When the QTDW drops to very weak amplitudes, the background wind decreases and reverses. During this time, the diurnal tide holds large amplitudes. These results support the notion that the variability of the diurnal tide is mainly attributable to the strong QTDW-induced changes in the background atmosphere, which was shown in the modeling study by Chang et al. (2011). Hence, both the nonlinear interaction and the background flow changes are responsible for the observed variation of the diurnal tide.

This paper presents characteristics of quasi-two-day waves (QTDWs) in the mesosphere and lower thermosphere (MLT) between 52° S and 52° N from 2002 to 2011 using TIMED/SABER temperature data. Spectral analysis suggests that dominant QTDW components at mid-high latitudes of the Southern Hemisphere (SH) and the Northern Hemisphere (NH) are (2.13, W3) and (2.04, W4), respectively. The most remarkable QTDW is (2.13, W3), which happened in the southern summer of 2002–2003 at 32° S from 60 to 90 km in altitude. Its downward phase propagation indicates upward propagation of the wave energy and a potential source region below 60 km. Analysis of horizontal wind fields in the same period shows the westward and southward propagation of (2.13, W3) and a possible reflection region above 90 km. Fundamental parameters of QTDWs present significant interhemispheric differences and interannual variations in statistical analysis. Amplitudes in the SH are twice larger than that in the NH, and vertical wavelengths are a little longer in the SH. QTDWs may endure stronger dissipation in southern summer because of shorter durations of their attenuation stages. Impact of the equatorial quasi-biennial-oscillation (QBO) on QTDWs can extend to mid-high latitudes of both hemispheres. It seems easier for QTDWs to propagate upward in the equatorial QBO's westerly phase in the lower stratosphere and easterly phase in the middle stratosphere. Interannual variations of QTDW strength may be influenced by solar activity as well. Strengths of QTDWs appear to be stronger (weaker) in the solar maximum (minimum)

The interaction between the tropopause inversion layer (TIL) and the inertial gravity wave (IGW) activities is first presented by using a high vertical resolution radiosonde data set at a midlatitude station, Boise, Idaho (43.57°N, 116.22°W), for the period 1998-2008. The tropopause-based vertical coordinate is used for the TIL detection, and for meticulously studying the IGW variation around the TIL, the broad spectral method is used for the IGW extraction. Generally, the TIL at the midlatitude station is stronger and thicker in winter and spring, which is consistent with previous studies. Our study confirmed the intense interaction between the TIL and IGW. It is found that the TIL not only could inhibit the upward propagation of IGWs from below but also imply the possible excitation links between the TIL and IGW. The results also indicate that the enhanced wind shear layer just 1 km above the tropopause may result in instability and finally leads to the IGW breaking and intensive turbulence. Subsequently, the IGW-induced intensive turbulence leads to strong wave energy dissipation and a downward heat flux. This downward heat transportation could significantly cool the tropopause, while it has only negligible thermal effect on the atmosphere above the tropopause. Then, the IGW-induced cooling at the tropopause makes the tropopause colder and sharper and finally forms the TIL. These suggest besides previously proposed mechanisms that IGWs also contribute greatly to the formation of TIL, which is consistent with a recent related simulation study.

We present an analysis of the responses of quasi 2 day waves (QTDWs) to the 2013 sudden stratosphere warming (SSW) in the mesosphere and lower thermosphere (MLT) region. The study is based on data collected by a meteor radar chain along the 120°E meridian in the Northern Hemisphere which consists of four stations at Mohe (52.5°N, 122.3°E), Beijing (40.3°N, 116.2°E), Wuhan (30.5°N, 114.6°E), and Sanya (18.3°N, 109.6°E). It is the first time that an enhancement of the QTDW in the neutral wind during the 2013 SSW is observed in the midlatitudes in the Northern Hemisphere. During the SSW, the amplification of the QTDW in the low latitudes is the most prominent and the direction of the mean zonal wind shows clear reversion from eastward to westward. The consistent variations of the QTDWs and the mean neutral wind at the four stations are very likely associated with the SSW.

[1] An extensive analysis of atmospheric tides in the low-latitude thermosphere and their responses to a major sudden stratospheric warming (SSW) event (18-23 January 2010) is presented. The analysis is based on observational data from the Arecibo dual-beam incoherent scatter radar. Important findings of the present study are as follows. (1) The diurnal tide with an evanescent phase structure dominates the F region meridional wind field. The diurnal tide has a peak amplitude of 45 m/s occurring at about 245 km, and it is very stable throughout the nine consecutive days' observation. Below 114 km, the vertical structures of the diurnal tide in the meridional and zonal components are consistent, which resemble the classical solar S 1, 1 tidal mode. (2) The F region semidiurnal tide is much weaker and has larger day-to-day variability than the diurnal tide. In the E region, the semidiurnal amplitudes in the meridional and zonal components grow continuously in the altitude ranges from 106 to 121 km and from 100 to 115 km, respectively. The vertical wavelength of the zonal component is estimated to be 45 km above 100 km, which is close to the solar S 2, 4 and S 2, 5 tidal modes. (3) The semidiurnal and terdiurnal tides respond strongly to the SSW while the impact that the SSW has on the diurnal tide in the meridional wind is limited. During the SSW event, the amplitudes of the semidiurnal and terdiurnal tides are enhanced in the F region but reduced in the upper E region.

An extensive analysis of quasi 5‐day waves (5DWs) in the mesosphere and lower thermosphere and their responses to a major sudden stratospheric warming (SSW) event (January 2013) are presented. The analysis is based on data conducted from a meteor radar chain in the period from December 2008 to November 2017 and Aura Microwave Limb Sounder satellite. The radar chain includes three stations located at Mohe (MH, 53.5°N, 122.3°E), Beijing (BJ, 40.3°N, 116.2°E), and Wuhan (WH, 30.5°N, 114.6°E). The 5DWs present clear interannual and seasonal variations, which are observed by both the radar wind data and Aura‐temperature data. Interestingly, the ter‐annual oscillation is found to be as important as the commonly recognized annual oscillation and semiannual oscillation at the three stations in both neutral wind components. The 5DWs are strong mainly during the August/September in the meridional component, while they are primarily enhanced in the period of January, April/May, and late summer in the zonal component. An enhancement of 5DWs is observed during the 2013 SSW event in the mesosphere and lower thermosphere region at the three stations. The amplitudes during the SSW are more than 2 times larger than the January average. The strength of the amplification is most prominent at MH and reduces as latitude decreases. According to the results obtained from the radar wind and Aura temperature, the enhanced 5DW modes are W1 at MH, and W2 at BJ and WH. Our results indicate that the amplification of the 5DWs is very likely associated with the 2013 SSW.