Dry Adiabatic Lapse Rate Research Articles

Field observations of Easter weather on Snowdon from 1969 to 2010

AbstractStudents from Bangor University made weather observations on the slopes of Snowdon in their Easter holidays from 1969 to 2010. The air temperature decreased with altitude at a rate of about 10 degCkm−1, close to the dry adiabatic lapse rate, although the gradient was less when raining. Water temperatures also decreased with height but wind speeds, on average, increased. The eastern flank of the mountain was noticeably wetter and less windy than the north. Over the four decades, air temperatures increased by an average of 1.6 degC, equivalent to the mountain shrinking by 160m, based on the observed lapse rate.

Abrupt warming and alpine glacial retreat through the last deglaciation in Alaska interrupted by modest Northern Hemisphere cooling

Abstract. Alpine glacier-based temperature reconstructions spanning the last deglaciation provide critical constraints on local to regional climate change and have been reported from several formerly glaciated regions around the world yet remain sparse from high-northern-latitude regions. Using newly and previously 10Be-dated moraines, we report paleo-glacier equilibrium line altitudes (ELAs) for 15 time slices spanning the Last Glacial Maximum (LGM) to the Little Ice Age (LIA) for a valley in the western Alaska Range. We translate our ELA reconstructions into a proxy for summer temperature by applying a dry adiabatic lapse rate at each reconstructed ELA relative to the outermost LIA moraine. We observe ∼4 °C warming through the last deglaciation at our site that took place in two steps following initial gradual warming: ∼1.5 °C abrupt warming at 16 ka, ∼2 kyr after the onset of global CO2 rise, and ∼2 °C warming at ∼15 ka, near the start of the Bølling. Moraine deposition and modest summer cooling during Heinrich Stadial 1 and the early Younger Dryas (YD) suggest that despite these events being expressed more strongly in wintertime, the classic blueprint of North Atlantic climate variability extends to the western Arctic region.

Determination of the Dynamics of Thunderstorms Through the Dry Adiabatic Lapse Rate and Environmental Lapse Rate

This research aims to determine the types of thunderstorms formed in the thickness of the cloud (determine the Dry adiabatic lapse rate (DALR) and Environmental lapse rate (ELR)) in the case of precipitation during the day. Data were taken by Temperature, Dew point, Atmospheric Pressure, and Height from re-analysis by the (ECMWF) for the heights (0-18000) m, the levels of pressure (1000-100) mbar, low cloud cover data, and the characteristic days ((18, 24, 27) February, 28 April, and 25 November) of the year 2018 for Baghdad station were chosen to obtain the largest possible number of clouds and their diversity to use them in calculating the cloud cover and weather stability in terms of calculating the daily change, temperature, dew point in addition to calculating the low cloud cover with altitude and atmospheric instability. The Sigma Plot program was used in this research to determine the base of clouds and thunderstorms. The change in temperature, Dew point, clouds base, and altitude was determined, then the cloud thickness, types, and classification were calculated. The clouds found are strong thunderstorm clouds characterized by thickness and height, such as the clouds of Nimbostratus (Ns) and Cumulonimbus (Cb).

Global Warming by Geothermal Heat from Fracking: Energy Industry's Enthalpy Footprints.

Hypothetical dry adiabatic lapse rate (DALR) air expansion processes in atmosphere climate models that predict global warming cannot be the causal explanation of the experimentally observed mean lapse rate (approx.−6.5 K/km) in the troposphere. The DALR hypothesis violates the 2nd law of thermodynamics. A corollary of the heat balance revision of climate model predictions is that increasing the atmospheric concentration of a weak molecular transducer, CO2, could only have a net cooling effect, if any, on the biosphere interface temperatures between the lithosphere and atmosphere. The greenhouse-gas hypothesis, moreover, does not withstand scientific scrutiny against the experimental data. The global map of temperature difference contours is heterogeneous with various hotspots localized within specific land areas. There are regional patches of significant increases in time-average temperature differences, (∆<T>) = 3 K+, in a ring around the arctic circle, with similar hotspots in Brazil, South Africa and Madagascar, a 2–3 K band across central Australia, SE Europe centred in Poland, southern China and the Philippines. These global-warming map hotspots coincide with the locations of the most intensive fracking operational regions of the shale gas industry. Regional global warming is caused by an increase in geothermal conductivity following hydraulic fracture operations. The mean lapse rate (d<T>/dz)z at the surface of the lithosphere will decrease slightly in the regions where these operations have enhanced heat transfer. Geothermal heat from induced seismic activity has caused an irreversible increase in enthalpy (H) input into the overall energy balance at these locations. Investigating global warming further, we report the energy industry’s enthalpy outputs from the heat generated by all fuel consumption. We also calculate a global electricity usage enthalpy output. The global warming index, <∆T-biosphere> since 1950, presently +0.875 K, first became non-zero in the early 1970’s around the same time as natural gas usage began and has increased linearly by 0.0175 K/year ever since. Le Chatelier’s principle, applied to the dissipation processes of the biosphere’s ΔH-contours and [CO2] concentrations, helps to explain the global warming statistics.

Adiabatic lapse rate of real gases.

We derive a formula for the dry adiabatic lapse rate of atmospheres composed of real gases. We restrict our study to those described by a family of two-parameter cubic equationsof state and the recent Guevara-Rodríguez noncubic equation. Since our formula depends on the adiabatic curves, we compute them all at once, considering molecules that can move, rotate, and vibrate, for any equationof state. To illustrate our results, we estimate the lapse rate of the troposphere of Titan, obtaining a better approximation to the observed data in some instances, when compared to the estimation provided by the virial expansion up to the third order.

Mach and Froude Numbers on Mars

Mars atmospheric global circulation models exhibit transonic jet streaks during northern winter, which motivates this study of the Mach number, Ma (the ratio of flow speed to the speed of sound), and Froude number, Fr (the ratio of flow speed to the speed of buoyancy waves), as a function of season and location. Two global reanalyses spanning Mars Years (MY) 24 to 32 are used as input, EMARS and OpenMARS. The study’s vertical coordinate is potential temperature, θ, ranging from θ = 400 to 1100 K (from z ≈ 32 to 66 km); the floor is set to the lowest level that avoids intersecting mountains. Area-weighted global means and standard deviations and 5 yr temporal means using the complete years MY 25, 26, 29, 30, and 31 are compared. EMARS and OpenMARS show general agreement below θ = 700 K (z ≈ 53 km), where the observational constraints are strongest, but can vary significantly at higher levels. Both reanalyses contain transonic jet streaks in every northern winter sampled. The Fr signal is roughly twice the Ma number signal, as expected where the temperature lapse rate is small compared to the dry adiabatic lapse rate. Mach numbers are similar in both reanalyses but show larger year-to-year variability in OpenMARS. Maps of standard deviations indicate a depression between the main peaks in Tharsis and higher variability in Mare Boreum than Mare Australe. The main conclusion is that the atmosphere of Mars routinely operates in the compressible regime (0.3 < Ma < 0.8), unlike Earth. Aspects of all flow-speed meteorology are discussed.

How does the background atmosphere affect the onset of the runaway greenhouse?

As the insolation of an Earth-like (exo)planet with a large amount of water increases, its surface and atmospheric temperatures also increase, eventually leading to a catastrophic runaway greenhouse transition. While some studies have shown that the onset of the runaway greenhouse may be delayed due to an overshoot of the outgoing longwave radiation (OLR) – compared to the Simpson-Nakajima threshold – by radiatively inactive gases, there is still no consensus on whether this is occurring and why. Here, we used a suite of 1D radiative-convective models to study the runaway greenhouse transition, with particular emphasis on taking into account the radical change in the amount of water vapour (from trace gas to dominant gas). The aim of this work is twofold: first, to determine the most important physical processes and parametrisations affecting the OLR; and second, to propose reference OLR curves for N2+H2O atmospheres. Through multiple sensitivity tests, we list and select the main important physical processes and parametrisations that need to be accounted for in 1D radiative-convective models to compute an accurate estimate of the OLR for N2+H2O atmospheres. The reference OLR curve is computed with a 1D model built according to the sensitivity tests. These tests also allow us to interpret the diversity of results already published in the literature. Moreover, we provide a correlated-k table able to reproduce line-by-line calculations with high accuracy. We find that the transition between an N2-dominated atmosphere and an H2O-dominated atmosphere induces an overshoot of the OLR compared to the (pure H2O) Simpson–Nakajima asymptotic limit. This overshoot is first due to a transition between foreign and self-broadening of the water absorption lines, and second to a transition between dry and moist adiabatic lapse rates.

Adiabatic lapse rate of nonideal gases: The role of molecular interactions and vibrations.

We report a formula for the dry adiabatic lapse rate that depends on the compressibility factor and the adiabatic curves. Then, to take into account the nonideal behavior of the gases, we consider molecules that can move, rotate, and vibrate and the information of molecular interactions through the virial coefficients. We deduce the compressibility factor in its virial expansion form and the adiabatic curves within the virial expansion up to any order. With this information and to illustrate the mentioned formula, we write the lapse rate for the ideal gas, and the virial expansion up to the second and third coefficient cases. To figure out the role of the virial coefficients and vibrations, under different atmospheric conditions, we calculate the lapse rate for Earth, Mars, Venus, Titan, and the exoplanet Gl 581d. Furthermore, for each one we consider three models in the virial expansion: van der Waals, square-well, and hard-sphere. Also, when possible, we compare our results to the experimental data. Finally, we remark that for Venus and Titan, which are under extreme conditions of pressure or temperature, our calculations are in good agreement with the observed values, in some instances.

Air temperature lapse rates and cloud cover in a hyper-oceanic climate

AbstractAir temperature lapse rates vary geographically and temporally. Sub-Antarctic Macquarie Island provides an opportunity to compare lapse rates between windward and leeward slopes in a hyper-oceanic climate. Lapse rates were steep by global standards, typically close to the dry adiabatic lapse rate despite the near-constant high humidity. Limited diurnal and seasonal variation occurs in lapse rates on Macquarie Island. High variability of lapse rates on the eastern (lee) slope in summer months and in the midday hours appears to be driven by solar radiation. No diurnal or seasonal pattern was evident on the western slope. Development of orographic cloud is expected to modify lapse rates, given the theoretical shift between dry and saturated adiabatic lapse rates that occurs with condensation of water vapour. Cloud cover was frequent, with higher elevations being under cloud 50% of the time, with no seasonal variation. However, cloud base level did not explain variation in lapse rates. Low cloud is likely to be of ecological importance because it influences fog precipitation, solar radiation and evapotranspiration. Year-round dominance of westerly airflows and limited seasonal variation in air temperature and humidity explain the limited seasonal variation in cloud cover and lapse rates on Macquarie Island.

The Moist Adiabat, Key of the Climate Response to Anthropogenic Forcing

A straightforward mechanism based on properties of the moist adiabat is proposed to construe the observed latitudinal and longitudinal distribution of the anthropogenic forcing efficiency. Considering precipitation patterns at the planetary scale, idealized environmental adiabats leading to low-pressure systems are deduced. When the climate system responds to a small perturbation, which reflects radiative forcing that follows increasing anthropogenic emissions, the dry and moist adiabatic lapse rates move away from each other as the temperature of the moist adiabat at the altitude z = 0 increases. When the atmosphere becomes unstable, under the influence of the perturbation, a positive feedback loop occurs because of a transient change in the emission level height of outgoing longwave radiation in the saturated absorption bands of water vapor. During these periods of instability, the perturbation of the climate system is exerted with the concomitant warming of the surface temperature. In contrast, the return of the surface temperature to its initial value before the development of the cyclonic system is very slow because heat exchanges are mainly ruled by latent and sensible heat fluxes. Consequently, the mean surface temperature turns out to result from successive events with asymmetrical surface–atmosphere heat exchanges. The forcing efficiency differs according to whether atmospheric instability has a continental or oceanic origin. Hence the rendition of the latitudinal and longitudinal distribution of the observed surface temperature response to anthropogenic forcing, which specifies in detail the mechanisms involved in the various climate systems, including the Arctic amplification.

Vertical profile observations of water vapor deuterium excess in the lower troposphere

Abstract. We use airborne measurements of water vapor (H2Ov) stable isotopologues and complementary meteorological observations to examine how boundary layer (BL) dynamics, cloud processing, and atmospheric mixing influence the vertical structure of δD, δ18O, and deuterium excess (d excess =δD–8×δ18O) in the BL, inversion layer (INV), and lower free troposphere (FT). Flights were conducted around two continental US cities in February–March 2016 and included vertical profiles extending from near the surface to ≤2 km. We examine observations from three unique case study flights in detail. One case study shows observations that are consistent with Rayleigh isotopic distillation theory coinciding with clear skies, dry adiabatic lapse rates within the boundary layer, and relatively constant vertical profiles of wind speed and wind direction. This suggests that the air mass retained the isotopic fingerprint of dehydration during moist adiabatic processes upwind of the study area. Also, observed d-excess values in the free troposphere were sometimes larger than Rayleigh theory predicts, which may indicate mixing of extremely dehydrated air from higher altitudes. The two remaining case studies show isotopic anomalies in the d-excess signature relative to Rayleigh theory and indicate cloud processes and complex boundary layer development. The most notable case study with stratocumulus clouds present had extremely low (negative) d-excess values at the interface of the inversion layer and the free troposphere, which is possibly indicative of cloud or rain droplet evaporation. We discuss how in situ H2Ov stable isotope measurements, and d excess in particular, could be useful for improving our understanding of water phase changes, transport, and mixing that occurs between the BL, INV, and FT.

Analysis of Lower Tropospheric Lapse Rate Trend over Port Harcourt Coastal City, Nigeria

Understanding the spatial distribution of temperature, especially the relationship between temperature and altitude, is essential for understanding both climatological and hydrological processes and their variabilities. This is because those processes are sensitive to air temperature, especially in sub humid tropical regions, where air temperature influences the movements of pollutants and controls exchanges of energy and water fluxes between land and atmosphere particularly within the lower troposphere. This study examined the trend of lower tropospheric lapse rate in the coastal area of Port Harcourt, Nigeria. Six years’ data (2010-2015) for temperature between 1000 mbar and 850 mbar pressure levels was retrieved from era-interim re-analysis platform for the analysis. The data was acquired at 6-hourly synoptic hours: 0000H, 0600H, 1200H and 1800H at 0.125° grid resolution. Findings from the computed environmental lapse rate (ELR) show that conditional instability with an annual lapse rate of 5.5°C/km persists at the area from January to December. It was revealed that the months of December and January constituted the highest ELR trends of 6.5°C/km and 5.9°C/km respectively. This indicates that the month of December assumes a normal tropospheric lapse rate trend. The average range of lapse rate trend in the area which is close to the moist adiabatic lapse rate (MALR) of 5.0°C/km than the dry adiabatic lapse rate (DALR) shows that the study atmospheric environment is rich in water vapour. The 6-hourly synoptic analysis of the ELR pattern shows that lapse rate range between 1°C/km - 6.4°C/km and 6.5°C/km - 10°C/km dominates throughout the year at 0000 - 0600 Hrs and 1200 - 1800 Hrs respectively. This demonstrates a higher and lower lapse rate trend during the day and night periods respectively. Relating study findings to the potential of air to disperse emissions in the area suggests that air emissions will be conveyed through far and near distances across the boundary layers due to the moderate dispersive potential of air regarding the closeness of the average ELR to the MALR. Policies that will ensure that pollutants are dispersed aloft especially emission stacks above 50 m is advocated in the city of Port Harcourt.

Observed behaviours of precipitable water vapour and precipitation intensity in response to upper air profiles estimated from surface air temperature

Extremely heavy precipitation affects human society and the natural environment, and its behaviour under a warming climate needs to be elucidated. Recent studies have demonstrated that observed extreme precipitation increases with surface air temperature (SAT) at approximately the Clausius–Clapeyron (CC) rate, suggesting that atmospheric water vapour content can explain the relationship between extreme precipitation and SAT. However, the relationship between atmospheric water vapour content and SAT is poorly understood due to the lack of reliable observations with sufficient spatial and temporal coverage for statistical analyses. Here, we analyse the relationship between atmospheric water vapour content and SAT using precipitable water vapour (PWV) derived from global positioning system satellites. A super-CC rate appears in hourly PWV when the SAT is below 16 °C, whereas the rate decreases at high SAT, which is different from the precipitation-SAT relationship. The effects of upper air temperature and water vapour can consistently explain the super-CC rate of PWV relative to SAT. The difference between moist and dry adiabatic lapse rates increases with SAT, in consequence of more ability to hold water vapour in the free atmosphere under higher SAT conditions; therefore, attainable PWV increases more rapidly than the CC rate as SAT increases.

Synoptic-Scale Environmental Features of the Long-Lasting Ice Pellet Event in Northern Japan on 10 April 2005

An extremely long ice pellet event with extensive episodic ice pellet falls occurred over northern Japan on 10 April 2005. The synoptic-scale environmental features of this event were examined based on Japan Meteorological Agency (JMA) mesoscale model (MSM) datasets. A synoptic-scale dry environment was formed under the melting layer ahead of the surface warm front by an intense secondary circulation. Back-trajectory analysis suggested that dry air was located to the south of the precipitating area and was conveyed to the precipitating area by strong geostrophic winds. The surface air at Sapporo, Japan, originated from the ocean surface to the southeast and was cooled to almost the same temperature as that of the sea surface (+3°C); that is, the minimum temperature at 600 m progressively decreased to −3°C at the dry adiabatic lapse rate, during the ice pellet event. Sapporo and its surrounding areas, which were at the southern edge of the precipitating area until the passage of the low pressure center and continued to experience midlevel dry and low-level cold inflows maintained by persistent synoptic-scale structures, were identified as the favorable locations for long-lasting ice pellets.

Application of K-Nearest Neighbor Technique to Predict Severe Thunderstorms

Machine learning techniques are used in different types of pattern recognition works. Nowadays, these techniques are applied in meteorological fields for prediction purpose. In this paper, the pattern to be recognized is the severe weather event of squall-thunderstorms. Prediction of severe thunderstorms are done here by applying K-Nearest Neighbor (K-NN) technique. K-NN is a very good classifier which can classify two classes of events „storm days‟ and „no storm days‟. It is a non-parametric method. Three types of weather parameters such as moisture difference, dry adiabatic lapse rate and vertical wind shear are considered here as predictors. Both surface as well as upper air data which are measured by radiosonde/ rawindsonde in the early morning are used in this case. Weather forecasting is a challenging job because of the dynamic behavior of the atmosphere. „Storm days‟ are predicted correctly more than 91% and both „storm and no storm days‟ are classified more than 82% accuracy, having a lead time around 12 hours.

Analysis of a Destructive Wind Storm on 16 November 2008 in Brisbane, Australia

AbstractDuring the late afternoon on 16 November 2008 the Brisbane (Queensland, Australia) suburb of “The Gap” experienced extensive wind damage caused by an intense local thunderstorm. The CP2 research radar nearby detected near-surface radial velocities exceeding 43 m s−1 above The Gap while hail size reports did not exceed golf ball size, and no tornadoes were reported. The storm environment was characterized by a layer of very moist near-surface air and strong storm-relative low-level flow, whereas the storm-relative winds aloft were weak. While the thermodynamic storm environment contained a range of downdraft-promoting ingredients such as a ~4-km-high melting level above a ~2-km-deep layer with nearly dry-adiabatic lapse rates mostly collocated with dry ambient air, a ~1-km-deep stable layer near the ground would generally lower expectations of destructive surface winds based on the downburst mechanism. Once observed reflectivities exceed 70 dBZ, downdraft cooling due to hail melting and downdraft acceleration based on hail loading are found to likely become nonnegligible forcing mechanisms. The event featured the close proximity of a hydrostatically and dynamically driven mesohigh at the base of the downdraft to a dynamically driven mesolow associated with a low-level circulation. This proximity was instrumental in the anisotropic horizontal acceleration of the near-ground outflow and the ultimate strength of the Gap storm surface winds. Weak storm-relative midlevel winds are speculated to have allowed the downdraft to descend close to the low-level circulation, which set up this strong horizontal perturbation pressure gradient.

Application of Pattern Recognition Techniques to Predict Severe Thunderstorms

Thunderstorm forecasting is a challenging job. Machine learning techniques are being applied nowadays in meteorological fields for prediction purpose. This study presents the application of different machine learning tools based on multiple correlation, Multi-layer Perceptron (MLP), K-nearest neighbor (K-nn) method, and modified K-nn method to predict seasonal severe thunderstorms associated with squall occurring in Kolkata, North-East India. The models are trained and tested with the radiosonde data recorded in the early morning at 00:00UTC. The predictors are moisture difference and dry adiabatic lapse rate at different geopotential heights of the atmosphere. Our aim in this paper is to find how much correctly one can nowcast 10 to 14 hours before the 'occurrence'/ 'no occurrence' of evening squall-storms by using a few upper air diagnostic predictors. Modified K-nn method is found to yield very promising prognostic information with high prediction accuracy. The results indicate that forecasting can be done correctly up to 82.02% both for 'squall-storm/no storm' events, and up to 91.11% for 'squall-storm' events using modified K-nn based approach. In this article, modified K-nn method is proved as the best method in comparison with the other methods for the squall-storm prediction.

Stable isotope ratios in precipitation and their relationship with meteorological conditions in the Kumaon Himalayas, India

Summary For the first time, environmental isotopic (δ2H, δ18O, 3H) data, predominantly based on precipitation samples in the Kumaon Himalayas, India, have been used to understand the influence of various meteorological factors governing rainout processes in the region. Further, the data are also used to understand the orographic effects in precipitation and to estimate the altitude effect in stable isotopic ratios in precipitation, etc. The interpretation of the isotopic data revealed that the source of moisture for winter (October–February) and summer (May) precipitation in the Kumaon Himalayas is mainly from the Western Disturbances whereas for the remaining period the source is monsoonal (southwest). The δ2Η−δ18O relationship in the local precipitation during the monsoon season shows a distinct seasonal effect, with a slope of 7.6. The winter and summer precipitation samples measured higher environmental 3H compared to southwest monsoon samples, thus indicating continental evaporated moisture. There is wide range of altitude effects (δ18O variation per 100 m elevation: −0.30‰ [July–August]; −0.57‰ [September]) with the mean altitude effect being −2.61‰ and −0.36‰ per 100 m elevation for δ2H and δ18O respectively. These values are different from that reported earlier for the region based on the isotopic compositions of springs/rivers samples. The ‘altitude effect’ in successive precipitation is basically a temperature dependent phenomenon and is explained on the basis of adiabatic cooling related rainout process (dry adiabatic lapse rate, moist adiabatic lapse rate and saturated adiabatic lapse rate for moist air mass). The altitude effect is found to be more reliable in case of δ2Η, as deuterium is least affected by secondary evaporation. The effect of secondary evaporation has been observed on the true “altitude effect”. Secondary evaporation of rainfall increases the oxygen isotopic ratios and the increase is directly proportional to the vertical distance travelled by the raindrops through air.

Influence of CO2 line profiles on radiative and radiative‐convective equilibrium states of the Venus lower atmosphere

Influence of CO2 line profiles on vertical temperature distributions in the radiative and radiative‐convective equilibria is examined in the Venus atmosphere. The CO2 opacity obtained by the Voigt (Lorentz) profile without the line cutoff is shown to be excessive since this opacity gives surface temperatures of about 860–1020 K in the radiative‐convective equilibrium. On the other hand, the opacity obtained by the extremely sub‐Lorentzian profiles of Pollack et al. (1993) and Tonkov et al. (1996) are underestimated; the surface temperature obtained with this opacity remains 600 K even in the radiative equilibrium. In this case, convection does not take place below the cloud layer because of the cloud opacity. It is also shown that Fukabori et al.'s (1986) and Meadows and Crisp's (1996) profiles, both of which have intermediate absorption coefficients, give temperature distributions close to the observed one in the radiative‐convective equilibrium. In these cases, the convection layer extends from the surface to 30–50 km altitudes. Then, the temperature distribution below the cloud layer is determined by a dry adiabatic lapse rate and the temperature near the cloud bottom. The surface temperature in the radiative‐convective equilibrium is strongly affected by the temperature near the cloud bottom in this situation. The detailed structure of the H2SO4 cloud must be taken into account to construct a realistic radiative transfer model.

Influence of gravity waves and tides on mesospheric temperature inversion layers: simultaneous Rayleigh lidar and MF radar observations

Abstract. Three nights of simultaneous Rayleigh lidar temperature measurements over Gadanki (13.5° N, 79.2° E) and medium frequency (MF) radar wind measurements over Tirunelveli (8.7° N, 77.8° E) have been analyzed to illustrate the possible effects due to tidal-gravity wave interactions on upper mesospheric inversion layers. The occurrence of tidal gravity wave interaction is investigated using MF radar wind measurements in the altitude region 86–90 km. Of the three nights, it is found that tidal gravity wave interaction occurred in two nights. In the third night, diurnal tidal amplitude is found to be significantly larger. As suggested in Sica et al. (2007), mesospheric temperature inversion seems to be a signature of wave saturation in the mesosphere, since the temperature inversion occurs at heights, when the lapse rate is less than half the dry adiabatic lapse rate.