Statistical analysis of inertial gravity wave parameters in the lower stratosphere over Northern China

Chen, Lei; Bian, Jianchun; Liu, Yi; Bai, Zhihui; Qiao, Sanzheng

doi:10.1007/s00382-018-4156-9

Cited by 7 publications

(13 citation statements)

References 26 publications

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“…Thus, the specific mechanism remains challenging to determine (Plougonven et al., 2003). In addition, Kelvin–Helmholtz instability (KHI) may interact with or act as a source for GWs (Chen et al., 2019; Fritts & Alexander, 2003). The KH billow evolution depends on various parameters, most critically the Richardson number ( Ri ).…”

Section: Introductionmentioning

confidence: 99%

Tropospheric Gravity Waves as Observed by the High‐Resolution China Radiosonde Network and Their Potential Sources

et al. 2022

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Lower atmospheric gravity waves (GWs) can significantly impact waves in the middle and upper atmospheres and are vital for turbulence generation. This paper puts the spotlight on the spatial–temporal variability of tropospheric GW total energy (ET) and its potential sources above four regions of interest (ROIs) gathered from high‐resolution radiosonde observations from the China Radiosonde Network during the years 2016–2019. The seasonality of ET above four ROIs shows different characteristics and is dependent on latitudes and underlying terrains, reaching its maximum identified in the winter at middle latitudes. Interestingly, the annual cycles of the maximal ET shift from 35°N in October to 25°N in March of the next year, triggered by the shift in the winter subtropical jet. Based on the random forests regressor, the jet stream between 200 and 125 hPa likely serves as the primary source for the observed GWs above the ROIs with low and middle latitudes, with relative contributions of around 60%. However, the Kelvin–Helmholtz instability between 800 and 125 hPa could be the most recognized source of GWs and contributes around 68.4% to the observed energy. During the rainy season, the ET under scenarios of convective precipitation is around 20% larger than the other. As well, as the near‐surface or low‐level wind interacts with a mountain barrier over the Tibetan Plateau region, 12.4% of the observed ET is attributed to the strength of the low‐level wind.

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Section: Introductionmentioning

confidence: 99%

Tropospheric Gravity Waves as Observed by the High‐Resolution China Radiosonde Network and Their Potential Sources

et al. 2022

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“…The ratio values vary between ~1.2 and ~6.0, showing negligible differences in magnitude at the three altitude intervals. Although the maximum ratio value here (~7.0) is larger than that shown in Wang et al [27], it is still acceptable because low-intrinsic frequency waves with a ratio smaller than 10 are classified as gravity waves [7,27,45]. Figure 3d-f show the global distributions of horizontal wavelengths averaged at the three altitude intervals during JJA 2006.…”

Section: Validation Of the Strategymentioning

confidence: 67%

“…Using the Stokes method (see Appendix A), these wind perturbations (u , v ) are further converted to gridded horizontal wind fluctuations parallel and perpendicular to the wave vector (u , v ⊥ ). Considering that the GW's hodograph traces out an ellipse and the ratio of the semiminor to semimajor axes is proportional to the ratio of the Coriolis frequency f and the intrinsic frequencyω [43], the intrinsic frequency of GWs is derived using Equation (4) [44,45]:…”

Section: Methods To Derive Vertical Wave Parameters Of Gwsmentioning

confidence: 99%

“…First, the value of ω/ f should be set greater than 1, because the gravity waves can exist only for the intrinsic frequencies that satisfy f < ω < N [1,43], where N is the Brunt-Väisälä frequency. Second, following [45], the maximum magnitude of ω/ f is set as 10 because an intrinsic frequency that is too large is not reliable and would make it difficult to explain the statistical results of inertia-gravity wave parameters [46].…”

Section: Methods To Derive Horizontal Wave Parameters Of Gwsmentioning

confidence: 99%

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Magnitudes of Gravity Wave Pseudomomentum Flux Derived by Combining COSMIC Radio Occultation and ERA-Interim Reanalysis Data

Luo

et al. 2019

Atmosphere

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In the present work, dry temperature profiles provided by the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation (RO) mission and the horizontal wind field provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis are combined for the first time to retrieve the magnitudes of gravity wave (GW) pseudomomentum flux (PMF). The vertical wave parameters, including Brunt–Väisälä frequencies, potential energy (Ep), and vertical wavelengths, are retrieved from RO temperature profiles. The intrinsic frequencies, which are retrieved from the horizontal wind field of ERA-Interim, are combined with the vertical wave parameters to derive the horizontal wavelengths and magnitudes of the PMF of GWs. The feasibility of this new strategy is validated first by comparing the distributions of GW parameters during June, July, and August (JJA) 2006 derived this way with those derived by previous studies. Then the seasonal and interannual variations of the distributions of GW PMF for three altitude ranges, 20–25 km, 25–30 km, and 30–35 km, over the globe during the seven years from June 2006 to May 2013 are presented. It is shown that the three altitude intervals share similar seasonal and interannual distribution patterns of GW PMF, while the magnitudes of GW PMF decrease with increased height and the hot spots of GW activity are the most discernable at the lowest altitude interval of 20–25 km. The maximums of PMF usually occur at latitudes around 60° in the winter hemispheres, where eastward winds prevail, and the second maximums exist over the subtropics of the summer hemispheres, where deep convection occurs. In addition, the influence of quasi-biennial oscillation (QBO) on both GW PMF and zonal winds is discernible over subtropical regions. The present work complements the GW PMF interannual variation patterns derived based on satellite observations by previous studies in terms of the altitude range, latitude coverage, and time period analyzed.

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“…On the one hand, the fourth‐order polynomial fitting adopted in this paper will obtain a smaller amplitude of the wave; on the other hand, the difference in local excitation process will also affect the results (Huang et al., 2018). GWs are strongest in winter and weakest in the monsoon (Chen et al., 2019; Venkat Ratnam et al., 2008; Zhang Shao Dong et al., 2012). However, in the stratosphere, the annual cycle has weakened significantly.…”

Section: Conclusion and Summarymentioning

confidence: 99%

Statistical Characteristics of Inertial Gravity Waves Over a Tropical Station in the Western Pacific Based on High‐Resolution GPS Radiosonde Soundings

Zhu

Sheng

et al. 2021

JGR Atmospheres

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The characteristics of gravity wave activity in tropical areas have been extensively explored, but at present, less attention has been paid to the activity of inertial gravity waves (IGWs) in the Western Pacific based on in‐situ detection data. Based on the radiosonde data over Guam (13.3°N, 144.4°E) for 6 years (2013–2018), the hodograph method and spectrum analysis are used to analyze the statistical characteristics of IGWs in the troposphere (2–14 km) and stratosphere (18–28 km). The gravity wave (GW) energy in the troposphere has clear annual cycle, with the strongest activity in winter and the weakest in monsoon. In the stratosphere, the periodic variation of wave energy is interrupted due to the 2016 quasi‐biennial oscillation (QBO) disruption reflected in the zonal wind field. In the troposphere, the quantity of up‐propagating GWs is close to that of the down‐propagating GWs, while in the stratosphere, they are almost up‐propagating GWs. The horizontal propagation direction of GWs is mainly northeast and southwest in both the troposphere and the stratosphere, since the weak background wind field does not produce significant filtering effect. The spectral amplitude based on the normalized temperature perturbation has clear uniform annual variations in the troposphere and stratosphere, which are the largest in winter and the smallest in monsoon. Due to the “saturation” process in the up‐propagating process of GWs, the spectral slope is more negative in the stratosphere.

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Statistical analysis of inertial gravity wave parameters in the lower stratosphere over Northern China

Cited by 7 publications

References 26 publications

Tropospheric Gravity Waves as Observed by the High‐Resolution China Radiosonde Network and Their Potential Sources

Tropospheric Gravity Waves as Observed by the High‐Resolution China Radiosonde Network and Their Potential Sources

Magnitudes of Gravity Wave Pseudomomentum Flux Derived by Combining COSMIC Radio Occultation and ERA-Interim Reanalysis Data

Statistical Characteristics of Inertial Gravity Waves Over a Tropical Station in the Western Pacific Based on High‐Resolution GPS Radiosonde Soundings

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