Aircraft measurements of gravity waves in the upper troposphere and lower stratosphere during the START08 field experiment

Abstract. This study analyzes in situ airborne measurements from the 2008 Stratosphere–Troposphere Analyses of Regional Transport (START08) experiment to characterize gravity waves in the extratropical upper troposphere and lower stratosphere (ExUTLS). The focus is on the second research flight (RF02), which took place on 21–22 April 2008. This was the first airborne mission dedicated to probing gravity waves associated with strong upper-tropospheric jet–front systems. Based on spectral and wavelet analyses of the in situ observations, along with a diagnosis of the polarization relationships, clear signals of mesoscale variations with wavelengths ~ 50–500 km are found in almost every segment of the 8 h flight, which took place mostly in the lower stratosphere. The aircraft sampled a wide range of background conditions including the region near the jet core, the jet exit and over the Rocky Mountains with clear evidence of vertically propagating gravity waves of along-track wavelength between 100 and 120 km. The power spectra of the horizontal velocity components and potential temperature for the scale approximately between ~ 8 and ~ 256 km display an approximate −5/3 power law in agreement with past studies on aircraft measurements, while the fluctuations roll over to a −3 power law for the scale approximately between ~ 0.5 and ~ 8 km (except when this part of the spectrum is activated, as recorded clearly by one of the flight segments). However, at least part of the high-frequency signals with sampled periods of ~ 20–~ 60 s and wavelengths of ~ 5–~ 15 km might be due to intrinsic observational errors in the aircraft measurements, even though the possibilities that these fluctuations may be due to other physical phenomena (e.g., nonlinear dynamics, shear instability and/or turbulence) cannot be completely ruled out.

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Aircraft measurements of gravity waves in the upper troposphere and lower stratosphere during the START08 Field Experiment

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-4725-2015 ◽

2015 ◽

Vol 15 (4) ◽

pp. 4725-4766 ◽

Cited By ~ 1

Author(s):

Fuqing Zhang ◽

Junhong Wei ◽

Meng Zhang ◽

K. P. Bowman ◽

L. L. Pan ◽

...

Keyword(s):

Gravity Waves ◽

Lower Stratosphere ◽

Power Spectra ◽

Small Scale ◽

Aircraft Measurements ◽

Upper Troposphere ◽

Long Wavelength ◽

Airborne Measurements ◽

Wide Range

Abstract. This study analyzes in situ airborne measurements from the 2008 Stratosphere–Troposphere Analyses of Regional Transport (START08) experiment to characterize gravity waves in the extratropical upper troposphere and lower stratosphere (ExUTLS) region. The focus is on the second research flight (RF02), which took place on 21–22 April 2008. This was the first airborne mission dedicated to probing gravity waves associated with strong upper-tropospheric jet-front systems. Based on spectral and wavelet analyses of the in situ observations, along with a diagnosis of the polarization relationships, clear signals of mesoscale variations with wavelengths ~50–500 km are found in almost every segment of the 8 h flight, which took place mostly in the lower stratosphere. The aircraft sampled a wide range of background conditions including the region near the jet core, the jet exit and over the Rocky Mountains. In contrast to the long wavelength mesoscale variations, smaller-scale wavelike oscillations below 50 km are found to be quite transient. In particular, aircraft measurements of several flight segments are dominated by signals with periods of ~20– ~60 s and wavelengths of ~5– ~15 km. We speculate that at least part of these nearly-periodic high-frequency signals are a result of intrinsic observational errors in the aircraft measurements or small-scale flight-altitude fluctuations that are difficult to fully characterize. Despite the presence of possibly spurious wave oscillations in several flight segments, the power spectra of horizontal winds and temperature averaged over the analyzed START08 flight segments follow closely the -5/3 power law.

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Highly resolved observations of trace gases in the lowermost stratosphere and upper troposphere from the Spurt project: an overview

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-283-2006 ◽

2006 ◽

Vol 6 (2) ◽

pp. 283-301 ◽

Cited By ~ 73

Author(s):

A. Engel ◽

H. Bönisch ◽

D. Brunner ◽

H. Fischer ◽

H. Franke ◽

...

Keyword(s):

Atmospheric Transport ◽

Trace Gases ◽

Potential Temperature ◽

Data Set ◽

Upper Troposphere ◽

Mixing Ratios ◽

Trace Species ◽

Wide Range ◽

Tropopause Region

Abstract. During SPURT (Spurenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region) we performed measurements of a wide range of trace gases with different lifetimes and sink/source characteristics in the northern hemispheric upper troposphere (UT) and lowermost stratosphere (LMS). A large number of in-situ instruments were deployed on board a Learjet 35A, flying at altitudes up to 13.7 km, at times reaching to nearly 380 K potential temperature. Eight measurement campaigns (consisting of a total of 36 flights), distributed over all seasons and typically covering latitudes between 35° N and 75° N in the European longitude sector (10° W–20° E), were performed. Here we present an overview of the project, describing the instrumentation, the encountered meteorological situations during the campaigns and the data set available from SPURT. Measurements were obtained for N2O, CH4, CO, CO2, CFC12, H2, SF6, NO, NOy, O3 and H2O. We illustrate the strength of this new data set by showing mean distributions of the mixing ratios of selected trace gases, using a potential temperature-equivalent latitude coordinate system. The observations reveal that the LMS is most stratospheric in character during spring, with the highest mixing ratios of O3 and NOy and the lowest mixing ratios of N2O and SF6. The lowest mixing ratios of NOy and O3 are observed during autumn, together with the highest mixing ratios of N2O and SF6 indicating a strong tropospheric influence. For H2O, however, the maximum concentrations in the LMS are found during summer, suggesting unique (temperature- and convection-controlled) conditions for this molecule during transport across the tropopause. The SPURT data set is presently the most accurate and complete data set for many trace species in the LMS, and its main value is the simultaneous measurement of a suite of trace gases having different lifetimes and physical-chemical histories. It is thus very well suited for studies of atmospheric transport, for model validation, and for investigations of seasonal changes in the UT/LMS, as demonstrated in accompanying and elsewhere published studies.

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Highly resolved observations of trace gases in the lowermost stratosphere and upper troposphere from the Spurt project: an overview

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-5081-2005 ◽

2005 ◽

Vol 5 (4) ◽

pp. 5081-5126

Author(s):

A. Engel ◽

H. Bönisch ◽

D. Brunner ◽

H. Fischer ◽

H. Franke ◽

...

Keyword(s):

Atmospheric Transport ◽

Trace Gases ◽

Potential Temperature ◽

Data Set ◽

Upper Troposphere ◽

Mixing Ratios ◽

Trace Species ◽

Wide Range ◽

Tropopause Region

Abstract. During SPURT (Spurenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region) we performed measurements of a wide range of trace gases with different lifetimes and sink/source characteristics in the northern hemispheric upper troposphere (UT) and lowermost stratosphere (LMS). A large number of in-situ instruments were deployed on board a Learjet 35A, flying at altitudes up to 13.7 km, at times reaching to nearly 380 K potential temperature. Eight measurement campaigns (consisting of a total of 36 flights), distributed over all seasons and typically covering latitudes between 35° N and 75° N in the European longitude sector (10° W–20° E), were performed. Here we present an overview of the project, describing the instrumentation, the encountered meteorological situations during the campaigns and the data set available from SPURT. Measurements were obtained for N2O, CH4, CO, CO2, CFC12, H2, SF6, NO, NOy, O3 and H2O. We illustrate the strength of this new data set by showing mean distributions of the mixing ratios of selected trace gases, using a potential temperature – equivalent latitude coordinate system. The observations reveal that the LMS is most stratospheric in character during spring, with the highest mixing ratios of O3 and NOy and the lowest mixing ratios of N2O and SF6. The lowest mixing ratios of NOy and O3 are observed during autumn, together with the highest mixing ratios of N2O and SF6 indicating a strong tropospheric influence. For H2O, however, the maximum concentrations in the LMS are found during summer, suggesting unique (temperature- and convection-controlled) conditions for this molecule during transport across the tropopause. The SPURT data set is presently the most accurate and complete data set for many trace species in the LMS, and its main value is the simultaneous measurement of a suite of trace gases having different lifetimes and physical-chemical histories. It is thus very well suited for studies of atmospheric transport, for model validation, and for investigations of seasonal changes in the UT/LMS, as demonstrated in accompanying and elsewhere published studies.

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The Momentum Budget in the Stratosphere, Mesosphere, and Lower Thermosphere. Part II: The In Situ Generation of Gravity Waves

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-17-0337.1 ◽

2018 ◽

Vol 75 (10) ◽

pp. 3635-3651 ◽

Cited By ~ 6

Author(s):

Ryosuke Yasui ◽

Kaoru Sato ◽

Yasunobu Miyoshi

Keyword(s):

Gravity Wave ◽

Gravity Waves ◽

Lower Thermosphere ◽

Shear Instability ◽

Wave Forcing ◽

Momentum Budget ◽

Mesosphere And Lower Thermosphere ◽

In Situ Generation ◽

Mlt Region

The contributions of gravity waves to the momentum budget in the mesosphere and lower thermosphere (MLT) is examined using simulation data from the Ground-to-Topside Model of Atmosphere and Ionosphere for Aeronomy (GAIA) whole-atmosphere model. Regardless of the relatively coarse model resolution, gravity waves appear in the MLT region. The resolved gravity waves largely contribute to the MLT momentum budget. A pair of positive and negative Eliassen–Palm flux divergences of the resolved gravity waves are observed in the summer MLT region, suggesting that the resolved gravity waves are likely in situ generated in the MLT region. In the summer MLT region, the mean zonal winds have a strong vertical shear that is likely formed by parameterized gravity wave forcing. The Richardson number sometimes becomes less than a quarter in the strong-shear region, suggesting that the resolved gravity waves are generated by shear instability. In addition, shear instability occurs in the low (middle) latitudes of the summer (winter) MLT region and is associated with diurnal (semidiurnal) migrating tides. Resolved gravity waves are also radiated from these regions. In Part I of this paper, it was shown that Rossby waves in the MLT region are also radiated by the barotropic and/or baroclinic instability formed by parameterized gravity wave forcing. These results strongly suggest that the forcing by gravity waves originating from the lower atmosphere causes the barotropic/baroclinic and shear instabilities in the mesosphere that, respectively, generate Rossby and gravity waves and suggest that the in situ generation and dissipation of these waves play important roles in the momentum budget of the MLT region.

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Climatology and long-term evolution of ozone and carbon monoxide in the UTLS at northern mid-latitudes, as seen by IAGOS from 1995 to 2013

10.5194/acp-2017-778 ◽

2017 ◽

Cited By ~ 1

Author(s):

Yann Cohen ◽

Hervé Petetin ◽

Valérie Thouret ◽

Virginie Marécal ◽

Béatrice Josse ◽

...

Keyword(s):

Carbon Monoxide ◽

Lower Stratosphere ◽

Boreal Summer ◽

Brazilian Coast ◽

Seasonal Cycles ◽

Western Coast ◽

Data Set ◽

Upper Troposphere ◽

North East ◽

Wide Range

Abstract. In situ measurements in the upper troposphere – lower stratosphere (UTLS) are performed in the framework of the European research infrastructure IAGOS (In-service Aircraft for a Global Observing System) for ozone since 1994 and for carbon monoxide since 2002. The flight tracks cover a wide range of longitudes in the northern extratropics, extending from the North American western coast (125° W) to the eastern Asian coast (135° E), and more recently over the northern Pacific ocean. Different tropical regions are also sampled frequently, such as the Brazilian coast, central and southern Africa, southeastern Asia and the western Maritime Continent. As a result, a new set of climatologies for O3 (Aug. 1994–Dec. 2013) and CO (Dec. 2001–Dec. 2013) in the upper troposphere (UT), tropopause layer and lower stratosphere (LS) are made available, including quasi-global gridded horizontal distributions, and seasonal cycles over eight well sampled regions of interest in the northern extratropics. The seasonal cycles generally show a summertime maximum in O3 and a springtime maximum in CO in the UT, in contrast with the systematic springtime maximum in O3 and the quasi-absence of seasonal cycle of CO in the LS. This study highlights some regional variabilities in the UT notably (i) a west-east difference of O3 in boreal summer with up to 15 ppb more O3 over central Russia compared with northeast America, (ii) a systematic west-east gradient of CO from 60° E to 140° E (especially noticeable in spring and summer with about 5 ppb by 10 degrees longitude), (iii) a broad spring/summer maximum of CO over North East Asia, and (iv) a spring maximum of O3 over Western North America. Thanks to almost 20 years of O3 and 12 years of CO measurements, the IAGOS database is a unique data set to derive trends in the UTLS. Trends in O3 in the UT are positive and statistically significant in most regions, ranging from +0.25 to +0.45 ppb yr−1, characterized by the significant increase of the lowest values of the distribution. No significant trends of O3 are detected in the LS. Trends of CO in the UT, tropopause and LS are all negative and statistically significant. The estimated slopes range from −1.37 to −0.59 ppb yr−1 , with a nearly homogeneous decrease of the lowest values of the monthly distribution (fifth percentile) contrasting with the high inter-regional variability of the highest values (95th percentile).

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In situ measurements of hydrogen cyanide in the upper troposphere/lower stratosphere during Arctic spring 2000

Journal of Geophysical Research Atmospheres ◽

10.1029/2001jd001033 ◽

2002 ◽

Vol 107 (D5) ◽

pp. SOL 47-1-SOL 47-6 ◽

Cited By ~ 2

Author(s):

A. A. Viggiano ◽

D. E. Hunton ◽

Thomas M. Miller ◽

John O. Ballenthin

Keyword(s):

Hydrogen Cyanide ◽

Lower Stratosphere ◽

In Situ Measurements ◽

Upper Troposphere

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An investigation into the characteristics of inertia gravity waves in the upper troposphere/lower stratosphere using a 205 MHz wind profiling radar

Remote Sensing Letters ◽

10.1080/2150704x.2017.1418991 ◽

2017 ◽

Vol 9 (3) ◽

pp. 284-293 ◽

Cited By ~ 2

Author(s):

Ajil Kottayil ◽

Karathazhiyath Satheesan ◽

Kesavapillai Mohankumar ◽

Sivan Chandran ◽

Titu Samson

Keyword(s):

Gravity Waves ◽

Lower Stratosphere ◽

Upper Troposphere ◽

Inertia Gravity Waves

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Characterization of the long-term radiosonde temperature biases in the upper troposphere and lower stratosphere using COSMIC and Metop-A/GRAS data from 2006 to 2014

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-4493-2017 ◽

2017 ◽

Vol 17 (7) ◽

pp. 4493-4511 ◽

Cited By ~ 21

Author(s):

Shu-peng Ho ◽

Liang Peng ◽

Holger Vömel

Keyword(s):

Lower Stratosphere ◽

Temperature Measurements ◽

Climate Data ◽

Upper Troposphere ◽

Global Trend ◽

The Mean ◽

Temperature Climate

Abstract. Radiosonde observations (RAOBs) have provided the only long-term global in situ temperature measurements in the troposphere and lower stratosphere since 1958. In this study, we use consistently reprocessed Global Positioning System (GPS) radio occultation (RO) temperature data derived from the COSMIC and Metop-A/GRAS missions from 2006 to 2014 to characterize the inter-seasonal and interannual variability of temperature biases in the upper troposphere and lower stratosphere for different radiosonde sensor types. The results show that the temperature biases for different sensor types are mainly due to (i) uncorrected solar-zenith-angle-dependent errors and (ii) change of radiation correction. The mean radiosonde–RO global daytime temperature difference in the layer from 200 to 20 hPa for Vaisala RS92 is equal to 0.20 K. The corresponding difference is equal to −0.06 K for Sippican, 0.71 K for VIZ-B2, 0.66 K for Russian AVK-MRZ, and 0.18 K for Shanghai. The global daytime trend of differences for Vaisala RS92 and RO temperature at 50 hPa is equal to 0.07 K/5 yr. Although there still exist uncertainties for Vaisala RS92 temperature measurement over different geographical locations, the global trend of temperature differences between Vaisala RS92 and RO from June 2006 to April 2014 is within ±0.09 K/5 yr. Compared with Vaisala RS80, Vaisala RS90, and sondes from other manufacturers, the Vaisala RS92 seems to provide the most accurate RAOB temperature measurements, and these can potentially be used to construct long-term temperature climate data records (CDRs). Results from this study also demonstrate the feasibility of using RO data to correct RAOB temperature biases for different sensor types.

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Initial MST radar observations of upper tropospheric-lower stratospheric duct-like structures over Jicamarca, Peru

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-11085-2012 ◽

2012 ◽

Vol 12 (22) ◽

pp. 11085-11093 ◽

Cited By ~ 2

Author(s):

Z. Li ◽

S. Naqvi ◽

A. J. Gerrard ◽

J. L. Chau ◽

Y. Bhattacharya

Keyword(s):

Gravity Waves ◽

Lower Stratosphere ◽

Physical Nature ◽

High Quality ◽

Data Set ◽

Upper Troposphere ◽

Atmospheric Fronts ◽

Mst Radar ◽

Wind Measurements

Abstract. Persistent wind jet structures along zonal and meridional fields, believed to be caused by stationary gravity waves, were detected in February 1999 in mesosphere-stratosphere-troposphere (MST) radar wind measurements of the troposphere and lower stratosphere over Jicamarca, Peru. Over a continuous seven day span of MST-data analyzed in this study, two days of observations showed signatures of wave-like structures in the upper troposphere/lower stratosphere wind jets associated with the phases of the stationary gravity waves. We believe these wave-like structures are ducted gravity waves. We present these initial observations, their characteristics, and the results of simple numerical simulations used in an attempt to mimic these observed features. Although a fair replication of the observed ducted structure in the numerical model is found, the observed period of ~90 min is nonetheless much longer than what is traditionally observed. As a result, the specific physical nature of the observed structures is not fully established. Nevertheless, given the high quality of the observations, we demonstrate here that continued analysis of this data set and concurrent modeling efforts will allow for a better understanding of Doppler ducts at high spatial and temporal resolution, and the results presented here can ultimately be applied to studies of middle atmospheric fronts, ducts, and bores.

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