scholarly journals Synchronization of atmospheric indicators at the last stage of earthquake preparation cycle

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Sergey A. Pulinets ◽  
Lidia I. Morozova ◽  
Ilya A. Yudin
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Optical Thickness ◽  
Chemical Potential ◽  
Time Interval ◽  
Strong Earthquakes ◽  
Coupling Process ◽  
Seismic Shock ◽  
Northwestern Iran ◽  
Last Stage

We consider the dynamics of different parameters in the boundary layer of atmosphere and low level cloud structure around the time of three recent moderate and strong earthquakes: Virginia M 5.8 earthquake on August 23 2011 in USA, Van M 7.1 earthquake on October 23 2011 in Turkey, and Northwestern Iran M 6.4 earthquake on August 11, 2012, Iran. Using as indicators the water vapor chemical potential correction value, aerosol optical thickness, and linear cloud structures appearance we discovered their coherence in space and time within the time interval 3-5 days before the seismic shock. Obtained results are interpreted as synergetic result of the lithosphere-atmosphere-ionosphere coupling process.

Why sometimes its simply sunny (in the trades)

2021 ◽  
Author(s):  
Bjorn Stevens ◽  
Ilya Serikov ◽  
Anna Lea Albright ◽  
Sandrine Bony ◽  
Geet George ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Marine Boundary Layer ◽  
Cloud Base ◽  
Lidar Signal ◽  
Cloud Base Height

<p>Cloud free skies are rare in the trades.  We analyze conditions in which cloud-free conditions prevail.  For this purpose Raman water vapor measurements from the Barbados Cloud Observatory, complemented by ship-based measurements during EUREC4A are used to explore water vapor variability in the marine boundary layer.   We explore the consistency of the inferred cloud base height with estimates of temperature and water vapor from the lidar signal, and examine the co-variability of these quantities.  After having established the properties of these measurements, we seek to use them as well as others, to explain in what ways periods of cloud-free conditions are maintained, investigating the hypothesis that only when the wind stills is it simply sunny.</p>

scholarly journals A Lidar at Clermont-Ferrand—France to describe the boundary layer dynamics, aerosols, cirrus and tropospheric water vapor

2018 ◽  
Vol 176 ◽  
pp. 05047
Author(s):  
J.L. Baray ◽  
P. Fréville ◽  
N. Montoux ◽  
A. Chauvigné ◽  
D. Hadad ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Vertical Profiles ◽  
Raman Lidar ◽  
Tropospheric Aerosols ◽  
Boundary Layer Dynamics

A Rayleigh-Mie-Raman LIDAR provides vertical profiles of tropospheric variables at Clermont-Ferrand (France) since 2008, in order to describe the boundary layer dynamics, tropospheric aerosols, cirrus and water vapor. It is included in the EARLINET network. We performed hardware/software developments in order to upgrade the quality, calibration and improve automation. We present an overview of the system and some examples of measurements and a preliminary geophysical analysis of the data.

scholarly journals A Framework to Study Mixing Processes in the Marine Boundary Layer Using Water Vapor Isotope Measurements

2018 ◽  
Vol 45 (5) ◽  
pp. 2524-2532 ◽  
Author(s):  
M. Benetti ◽  
J.‐L. Lacour ◽  
A. E. Sveinbjörnsdóttir ◽  
G. Aloisi ◽  
G. Reverdin ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Marine Boundary Layer ◽  
Mixing Processes ◽  
Isotope Measurements

Subcloud and Cloud-Base Latent Heat Fluxes during Shallow Cumulus Convection

2019 ◽  
Vol 77 (3) ◽  
pp. 1081-1100 ◽  
Author(s):  
Neil P. Lareau
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Latent Heat ◽  
Surface Fluxes ◽  
Heat Fluxes ◽  
Cloud Base ◽  
Cumulus Convection ◽  
Mixing Ratio ◽  
Convective Boundary ◽  
Water Vapor Mixing Ratio

Abstract Doppler and Raman lidar observations of vertical velocity and water vapor mixing ratio are used to probe the physics and statistics of subcloud and cloud-base latent heat fluxes during cumulus convection at the ARM Southern Great Plains (SGP) site in Oklahoma, United States. The statistical results show that latent heat fluxes increase with height from the surface up to ~0.8Zi (where Zi is the convective boundary layer depth) and then decrease to ~0 at Zi. Peak fluxes aloft exceeding 500 W m−2 are associated with periods of increased cumulus cloud cover and stronger jumps in the mean humidity profile. These entrainment fluxes are much larger than the surface fluxes, indicating substantial drying over the 0–0.8Zi layer accompanied by moistening aloft as the CBL deepens over the diurnal cycle. We also show that the boundary layer humidity budget is approximately closed by computing the flux divergence across the 0–0.8Zi layer. Composite subcloud velocity and water vapor anomalies show that clouds are linked to coherent updraft and moisture plumes. The moisture anomaly is Gaussian, most pronounced above 0.8Zi and systematically wider than the velocity anomaly, which has a narrow central updraft flanked by downdrafts. This size and shape disparity results in downdrafts characterized by a high water vapor mixing ratio and thus a broad joint probability density function (JPDF) of velocity and mixing ratio in the upper CBL. We also show that cloud-base latent heat fluxes can be both positive and negative and that the instantaneous positive fluxes can be very large (~10 000 W m−2). However, since cloud fraction tends to be small, the net impact of these fluxes remains modest.

The Effect of Boundary Layer Separation on Accuracy of Flow Measurement Using the Gibson Method

2007 ◽  
Author(s):  
F. Z. Sierra ◽  
A. Adamkowski ◽  
G. Urquiza ◽  
J. Kubiak ◽  
H. Lara ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Cross Section ◽  
Flow Rate ◽  
Pressure Difference ◽  
Proper Time ◽  
Effective Cross Section ◽  
Boundary Layer Separation ◽  
Water Hammer ◽  
Time Interval ◽  
Geometry Factor

The Gibson method utilizes the effect of water hammer phenomenon (hydraulic transients) in a pipeline for flow rate determination. The method consists in measuring a static pressure difference, which occurs between two cross-sections of the pipeline as a result of a temporal change of momentum from t0 to t1. This condition is induced when the water flow in the pipeline is stopped suddenly using a cut-off device. The flow rate is determined by integrating, within a proper time interval, the measured pressure difference change caused by the water hammer (inertia effect). However, several observations demonstrate that changes of pipeline geometry like diameter change, bifurcations, or direction shift by elbows may produce an effect on the computation of the flow rate. The paper focuses on this effect. Computational simulations have shown that the boundary layer separates when the flow faces sudden changes like these mentioned to above. The separation may reduce the effective cross section area of flow modifying a geometry factor involved into the computation of the flow rate. The remainder is directed to quantify the magnitude of such a factor under the influence of pipeline geometry changes. Results of numerical computations are discussed on the basis of how cross section reductions impact on the geometry factor magnitude and consequently on the mass flow rate.

scholarly journals Spaceborne differential absorption radar water vapor retrieval capabilities in tropical and subtropical boundary layer cloud regimes

2021 ◽  
Vol 14 (10) ◽  
pp. 6443-6468
Author(s):  
Richard J. Roy ◽  
Matthew Lebsock ◽  
Marcin J. Kurowski
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Trade Wind ◽  
Retrieval Algorithm ◽  
Line Center ◽  
Vertical Resolution ◽  
Horizontal Integration ◽  
Differential Absorption ◽  
Near Surface ◽  
Cloud Regimes

Abstract. Differential absorption radar (DAR) near the 183 GHz water vapor absorption line is an emerging measurement technique for humidity profiling inside of clouds and precipitation with high vertical resolution, as well as for measuring integrated water vapor (IWV) in clear-air regions. For radar transmit frequencies on the water line flank away from the highly attenuating line center, the DAR system becomes most sensitive to water vapor in the planetary boundary layer (PBL), which is a region of the atmosphere that is poorly resolved in the vertical by existing spaceborne humidity and temperature profiling instruments. In this work, we present a high-fidelity, end-to-end simulation framework for notional spaceborne DAR instruments that feature realistically achievable radar performance metrics and apply this simulator to assess DAR's PBL humidity observation capabilities. Both the assumed instrument parameters and radar retrieval algorithm leverage recent technology and algorithm development for an existing airborne DAR instrument. To showcase the capabilities of DAR for humidity observations in a variety of relevant PBL settings, we implement the instrument simulator in the context of large eddy simulations (LESs) of five different cloud regimes throughout the trade-wind subtropical-to-tropical cloud transition. Three distinct DAR humidity observations are investigated: IWV between the top of the atmosphere and the first detected cloud bin or Earth's surface; in-cloud water vapor profiles with 200 meter vertical resolution; and IWV between the last detected cloud bin and the Earth's surface, which can provide a precise measurement of the sub-cloud humidity. We provide a thorough assessment of the systematic and random errors for all three measurement products for each LES case and analyze the humidity precision scaling with along-track measurement integration. While retrieval performance depends greatly on the specific cloud regime, we find generally that for a radar with cross-track scanning capability, in-cloud profiles with 200 m vertical resolution and 10 %–20 % uncertainty can be retrieved for horizontal integration distances of 100–200 km. Furthermore, column IWV can be retrieved with 10 % uncertainty for 10–20 km of horizontal integration. Finally, we provide some example science applications of the simulated DAR observations, including estimating near-surface relative humidity using the cloud-to-surface column IWV and inferring in-cloud temperature profiles from the DAR water vapor profiles by assuming a fully saturated environment.

scholarly journals Identification of Precursory Anomalies before Moderate-strong Earthquakes in Junction of Shanxi-Hebei-Inner Mongolia Area

2020 ◽  
Vol 206 ◽  
pp. 01011
Author(s):  
Li Hong
Keyword(s):  
Standard Deviation ◽  
Inner Mongolia ◽  
Strong Earthquake ◽  
Earthquake Magnitude ◽  
Parameter Analysis ◽  
Time Interval ◽  
Study Region ◽  
Strong Earthquakes ◽  
Spectrum Method ◽  
Prediction Efficiency

In this paper, we take the Junction of Shanxi-Hebei-Inner Mongolia area as study region using earthquake corresponding relevancy spectrum method (ECRS method) to identify comprehensive precursory anomalies before moderate-strong earthquake. On base of single-parameter relevancy spectrum database with target earthquake magnitude as Ms4.7 and initial earthquake magnitude as Ms1, we carry on multi-parameter analysis and find that result with time interval of 9 months and anomaly threshold with 0.40 times standard deviation has better prediction efficiency. Its anomaly corresponding rate and earthquake corresponding rate are 6/10 and 9/9 respectively.

scholarly journals Reply to: "Tropical cirrus and water vapor: an effective Earth infrared iris feedback?"

2002 ◽  
Vol 2 (2) ◽  
pp. 99-101 ◽  
Author(s):  
M.-D. Chou ◽  
R. S. Lindzen ◽  
A. Y. Hou
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Water Vapor ◽  
Surface Temperature ◽  
Climate Sensitivity ◽  
Physical Meaning ◽  
Radiative Forcing ◽  
Sea Surface ◽  
Boundary Layer Clouds ◽  
High Level

Abstract. In assessing the iris effect suggested by Lindzen et al. (2001), Fu et al. (2002) found that the response of high-level clouds to the sea surface temperature had an effect of reducing the climate sensitivity to external radiative forcing, but the effect was not as strong as LCH found. The approach of FBH to specifying longwave emission and cloud albedos appears to be inappropriate, and the derived cloud optical properties may not have real physical meaning. The cloud albedo calculated by FBH is too large for cirrus clouds and too small for boundary layer clouds, which underestimates the iris effect.

Two months of measurements with an autonomous thermodynamic Raman lidar in Lindenberg

2021 ◽  
Author(s):  
Diego Lange Vega ◽  
Andreas Behrendt ◽  
Volker Wulfmeyer
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Inversion Layer ◽  
Measurement Range ◽  
High Accuracy ◽  
Free Troposphere ◽  
Raman Lidar ◽  
Backscatter Coefficient ◽  
Geophysical Research ◽  
Turbulence Scale

<p>Between 15 July 2020 and 19 September 2021, the Atmospheric Raman Temperature and Humidity Sounder (ARTHUS) collected data at the Lindenberg Observatory of the Deutscher Wetterdienst (DWD), including temperature and water vapor mixing ratio with a high temporal and range resolution.</p> <p>During the operation period, very stable 24/7 operation was achieved, and ARTHUS demonstrated that is capable to observe the atmospheric boundary layer and lower free troposphere during both daytime and nighttime up to the turbulence scale, with high accuracy and precision, and very short latency. During nighttime, the measurement range increases even up to the tropopause and lower stratosphere.</p> <p>ARTHUS measurements resolve the strength of the inversion layer at the planetary boundary layer top, elevated lids in the free troposphere, and turbulent fluctuations in water vapor and temperature, simultaneously (Lange et al., 2019, Wulfmeyer et al., 2015). In addition to thermodynamic variables, ARTHUS provides also independent profiles of the particle backscatter coefficient and the particle extinction coefficient from the rotational Raman signals at 355 nm with much better resolution than a conventional vibrational Raman lidar.</p> <p>At the conference, highlights of the measurements will be presented. Furthermore, the statistics of more than 150 comparisons with local radiosondes will be presented which confirm the high accuracy of the temperature and moisture measurements of ARTHUS.</p> <p><strong><em>Acknowledgements</em></strong></p> <p>The development of ARTHUS was supported by the Helmholtz Association of German Research Centers within the project Modular Observation Solutions for Earth Systems (MOSES). The measurements in Lindenberg were funded by DWD.</p> <p><strong><em>References </em></strong></p> <p>Lange, D., Behrendt, A., and Wulfmeyer, V. (2019). Compact operational tropospheric water vapor and temperature Raman lidar with turbulence resolution. <em>Geophysical Research Letters</em>, 46. https://doi.org/10.1029/2019GL085774</p> <p>Wulfmeyer, V., R. M. Hardesty, D. D. Turner, A. Behrendt, M. P. Cadeddu, P. Di Girolamo, P. Schlüssel, J. Van Baelen, and F. Zus (2015), A review of the remote sensing of lower tropospheric thermodynamic profiles and its indispensable role for the understanding and the simulation of water and energy cycles, <em>Rev. Geophys.</em>, 53,819–895, doi:10.1002/2014RG000476</p>

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