Vertical profiles of small-scale temperature structure in the atmosphere

1973 ◽  
Vol 4 (1-4) ◽  
pp. 169-177 ◽  
Author(s):  
C. E. Coulman
Keyword(s):  
Small Scale ◽  
Temperature Structure ◽  
Vertical Profiles ◽  
Scale Temperature

Centimeter-scale-resolution airborne temperature measurements in clouds and in marine surface layer during EUREC4A 

2021 ◽  
Author(s):  
Stanisław Król ◽  
Szymon Malinowski ◽  
Wojciech Kumala ◽  
Jakub Nowak ◽  
Robert Grosz ◽  
...  
Keyword(s):  
Surface Layer ◽  
Sampling Rate ◽  
Temperature Measurements ◽  
Small Scale ◽  
Temperature Structure ◽  
Scale Temperature ◽  
Marine Surface Layer ◽  
Marine Surface ◽  
Temperature Records

<p><span>Characterization of small-scale temperature structure of convective clouds and their environment is crucial to understand turbulent entrainment, mixing and its effect on cloud dynamics and microphysics. A newly constructed ultra-fast thermometer UFT2, developed from the former UFT-M, allowing for temperature measurements in clouds with the resolution better than few centimeters, was deployed on the British Antarctic Survey Twin-Otter research aircraft in the course of the EUREC4A research campaign. The goal was to perform first ever fine-scale temperature characterization of subtropical marine warm cumulus clouds.</span></p><p><span>The prototype instrument worked relatively well and allow to collect data from 7 of 17 research flights, including hundreds of cloud penetrations and segments of flights in the marine surface layer. Data, collected with 20 kHz sampling rate, after filtering and averaging allowed to achieve physical resolution of ~3cm at ~60m/s true air speed of the aircraft.</span></p><p><span>Performance of the UFT-2 sensor and its calibration will be discussed. The discussion will be illustrated with examples of multi-scale temperature records collected in cloud interiors, cloud edges, cloud shells at various altitudes as well as in the marine surface layer ~30 m above the sea level.</span></p>

scholarly journals Microstructure observations during the spring 2011 STRATIPHYT-II cruise in the Northeast Atlantic

2012 ◽  
Vol 9 (3) ◽  
pp. 2153-2186
Author(s):  
E. Jurado ◽  
H. A. Dijkstra ◽  
H. J. van der Woerd
Keyword(s):  
Mixed Layer ◽  
Small Scale ◽  
Vertical Profiles ◽  
Data Set ◽  
Northeast Atlantic ◽  
Unique Data ◽  
Eddy Diffusivities ◽  
Scale Temperature ◽  
Spatial Coverage ◽  
Layer Increase

Abstract. Small-scale temperature and conductivity variations have been measured in the upper 100 m of the Northeast Atlantic during the STRATIPHYT-II cruise (Las Palmas–Reykjavik, 6 April–3 May 2011). The measurements were done at midday and comprised 2 to 15 vertical profiles at each station. The derived turbulent quantities show a transition between weakly-stratified and well-mixed waters, which was centered at about 48° N. The temperature eddy diffusivities, KT, range from 10−5 to 100 m2s−1 in the weakly-stratified stations, and range from 3 × 10−4 to 2 × 100 m2s−1 in the well-mixed stations. The turbulent kinetic energy dissipation rates, ε, range from 3 × 10−8 to 2 × 10−6m2s−3 south of the transition zone, and from 10−7 to 10−5m2s−3 north of it. The station-averaged KT values throughout the mixed layer increase exponentially with the wind speed. The station-averaged ε values throughout the mixed layer scale with the wind stress similarity variable, u*3/(−κ z), with a scaling factor of about 1.8 in the wind-dominated stations. The values of KT and ε are about 10 times higher compared to the values measured at the same stations in July 2009. The results presented here constitute a unique data set giving large spatial coverage of upper ocean spring turbulence quantities.

scholarly journals Characterization of Arctic mixed-phase cloud properties at small scale and coupling with satellite remote sensing

2017 ◽  
Author(s):  
Guillaume Mioche ◽  
Olivier Jourdan ◽  
Julien Delanoë ◽  
Christophe Gourbeyre ◽  
Guy Febvre ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Crystal Size ◽  
Mixed Phase ◽  
Ice Crystals ◽  
Small Scale ◽  
Vertical Profiles ◽  
Liquid Droplets ◽  
Ice Crystal ◽  
High Concentration ◽  
Ice Crystal Size

Abstract. This study aims to characterize the microphysical and optical properties of ice crystals and supercooled liquid droplets within low-level Arctic mixed-phase clouds (MPC). We compiled and analyzed cloud in situ measurements from 4 airborne campaigns (18 flights, 71 vertical profiles in MPC) over the Greenland Sea and the Svalbard region. Cloud phase discrimination and representative vertical profiles of number, size, mass and shapes of ice crystals and liquid droplets are assessed. The results show that the liquid phase dominates the upper part of the MPC with high concentration of small droplets (120 cm−3, 15&tinsp;μm), and averaged LWC around 0.2 g m−3. The ice phase is found everywhere within the MPC layers, but dominates the properties in the lower part of the cloud and below where ice crystals precipitate down to the surface. The analysis of the ice crystal morphology highlights that irregulars and rimed are the main particle habit followed by stellars and plates. We hypothesize that riming and condensational growth processes (including the Wegener-Bergeron-Findeisein mechanism) are the main growth mechanisms involved in MPC. The differences observed in the vertical profiles of MPC properties from one campaign to another highlight that large values of LWC and high concentration of smaller droplets are possibly linked to polluted situations which lead to very low values of ice crystal size and IWC. On the contrary, clean situations with low temperatures exhibit larger values of ice crystal size and IWC. Several parameterizations relevant for remote sensing or modeling are also determined, such as IWC (and LWC) – extinction relationship, ice and liquid integrated water paths, ice concentration and liquid water fraction according to temperature. Finally, 4 flights collocated with active remote sensing observations from CALIPSO and CloudSat satellites are specifically analyzed to evaluate the cloud detection and cloud thermodynamical phase DARDAR retrievals. This comparison is valuable to assess the sub-pixel variability of the satellite measurements as well as their shortcomings/performance near the ground.

scholarly journals On the short-term variability of turbulence and temperature in the winter mesosphere

2018 ◽  
Vol 36 (4) ◽  
pp. 1099-1116
Author(s):  
Gerald A. Lehmacher ◽  
Miguel F. Larsen ◽  
Richard L. Collins ◽  
Aroh Barjatya ◽  
Boris Strelnikov
Keyword(s):  
Attitude Control ◽  
Large Scale ◽  
Lower Thermosphere ◽  
Density Fluctuations ◽  
Large Temperature ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Temperature Structure ◽  
Wind Shears

Abstract. Four mesosphere–lower thermosphere temperature and turbulence profiles were obtained in situ within ∼30 min and over an area of about 100 by 100 km during a sounding rocket experiment conducted on 26 January 2015 at Poker Flat Research Range in Alaska. In this paper we examine the spatial and temporal variability of mesospheric turbulence in relationship to the static stability of the background atmosphere. Using active payload attitude control, neutral density fluctuations, a tracer for turbulence, were observed with very little interference from the payload spin motion, and with high precision (<0.01 %) at sub-meter resolution. The large-scale vertical temperature structure was very consistent between the four soundings. The mesosphere was almost isothermal, which means more stratified, between 60 and 80 km, and again between 88 and 95 km. The stratified regions adjoined quasi-adiabatic regions assumed to be well mixed. Additional evidence of vertical transport and convective activity comes from sodium densities and trimethyl aluminum trail development, respectively, which were both observed simultaneously with the in situ measurements. We found considerable kilometer-scale temperature variability with amplitudes of 20 K in the stratified region below 80 km. Several thin turbulent layers were embedded in this region, differing in width and altitude for each profile. Energy dissipation rates varied between 0.1 and 10 mW kg−1, which is typical for the winter mesosphere. Very little turbulence was observed above 82 km, consistent with very weak small-scale gravity wave activity in the upper mesosphere during the launch night. On the other hand, above the cold and prominent mesopause at 102 km, large temperature excursions of +40 to +70 K were observed. Simultaneous wind measurements revealed extreme wind shears near 108 km, and combined with the observed temperature gradient, isolated regions of unstable Richardson numbers (0<Ri<0.25) were detected in the lower thermosphere. The experiment was launched into a bright auroral arc under moderately disturbed conditions (Kp∼5).

scholarly journals Modulation of Small-Scale Turbulence by Ducted Gravity Waves in the Nocturnal Boundary Layer

2008 ◽  
Vol 65 (4) ◽  
pp. 1414-1427 ◽  
Author(s):  
Y. P. Meillier ◽  
R. G. Frehlich ◽  
R. M. Jones ◽  
B. B. Balsley
Keyword(s):  
Boundary Layer ◽  
Gravity Waves ◽  
Richardson Number ◽  
Potential Temperature ◽  
Nocturnal Boundary Layer ◽  
Small Scale ◽  
Temperature Structure ◽  
Turbulence Measurements ◽  
Gradient Richardson Number ◽  
Scale Turbulence

Abstract Constant altitude measurements of temperature and velocity in the residual layer of the nocturnal boundary layer, collected by the Cooperative Institute for Research in Environmental Sciences (CIRES) Tethered Lifting System (TLS), exhibit fluctuations identified by previous work (Fritts et al.) as the signature of ducted gravity waves. The concurrent high-resolution TLS turbulence measurements (temperature structure constant C2T and turbulent kinetic energy dissipation rate ɛ) reveal the presence of patches of enhanced turbulence activity that are roughly synchronized with the troughs of the temperature and velocity fluctuations. To investigate the potentially dominant role ducted gravity waves might play on the modulation of atmospheric stability and therefore, on turbulence, time series of the wave-modulated gradient Richardson number (Ri) and of the vertical gradient of potential temperature ∂θ/∂z(t) are computed numerically and compared to the TLS small-scale turbulence measurements. The results of this study agree with the predictions of previous theoretical studies (i.e., wave-generated fluctuations of temperature and velocity modulate the gradient Richardson number), resulting in periodic enhancements of turbulence at Ri minima. The patches of turbulence observed in the TLS dataset are subsequently identified as convective instabilities generated locally within the unstable phase of the wave.

The Origin of High Ice Crystal Number Densities in Cirrus Clouds

2005 ◽  
Vol 62 (7) ◽  
pp. 2568-2579 ◽  
Author(s):  
C. R. Hoyle ◽  
B. P. Luo ◽  
T. Peter
Keyword(s):  
Cirrus Clouds ◽  
Small Scale ◽  
Ice Crystal ◽  
Cooling Rates ◽  
Density Distributions ◽  
In Situ Forming ◽  
Independent Particle ◽  
Scale Temperature ◽  
High Cooling Rates ◽  
Homogeneous Freezing

Abstract Recent measurements with four independent particle instruments in cirrus clouds, which formed without convective or orographic influence, report high number densities of ice particles (as high as nice = 50 cm−3) embedded in broad density distributions (nice = 0.1–50 cm−3). It is shown here that small-scale temperature fluctuations related to gravity waves, mechanical turbulence, or other small-scale air motions are required to explain these observations. These waves have typical peak-to-peak amplitudes of 1–2 K and frequencies of up to 10 h−1, corresponding to instantaneous cooling rates of up to 60 K h−1. Such waves remain unresolved in even the most advanced state-of-the-art global atmospheric models. Given the ubiquitous nature of these fluctuations, it is suggested that the character of young in situ forming cirrus clouds is mostly determined by homogeneous freezing of ice in solution droplets, driven by a broad range of small-scale fluctuations (period ∼a few minutes) with moderate to high cooling rates (1–100 K h−1).

Micro-Scale Thermal Sensor Manufacturing for Semiconductor Furnace Chamber

2012 ◽  
Author(s):  
Hongcheon Yang ◽  
Jun Young Kim ◽  
Kwang-Sun Kim
Keyword(s):  
Semiconductor Device ◽  
Furnace Chamber ◽  
Small Scale ◽  
Thermal Sensor ◽  
Micro Scale ◽  
Thermoelectric Voltage ◽  
Scale Temperature ◽  
Pattern Size ◽  
Different Temperatures ◽  
Analog Voltage

As the demand of complex and small scale semiconductor devices has been increased, the measurement technologies were developed to meet the accurate requirement in semiconductor manufacturing process. The uniform temperature requirement on the wafer is the major factor related to the semiconductor device yield. It is normally acquired from the thermocouples following the inner wall of the chamber. However, since the temperature difference between the wall of equipment and the surface of wafer is existed, the actual wafer temperature is commonly measured by a thermocouple wafer to calibrate the temperature measurement accuracy of the equipment. However, as the diameter of the commercial thermocouple wires is larger than the recently demanded pattern size, the TC wafer has not been able to measure the micro scale temperature differences on the micro patterned wafer. We, therefore, designed a micro-scale thermal sensor. The developed sensor has 37 sets of the measurement points on a 4-inch silicon wafer. The size of the measurement point is approximate to 16 um2. Two alloys, chromel and alumel which are as same as the materials of the K-type thermocouple are used to generate the thermoelectric voltage. The sensor has the temperature range of −200°C to 1300°C. The commercial K-type thermocouple extension wires are connected to the pads of the sensor array and they transfer the analog voltage data to a data acquisition device (DAQ). The sensor was calibrated by comparing the EMF voltage at different temperatures to the standard thermocouple EMF voltage. With the developed micro-scale thermal sensor system, the temperature distribution of the wafer in the furnace chamber is obtained.

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