Investigating contrails within cirrus clouds

2020 ◽  
Author(s):  
Peter Bräuer ◽  
Hanna Weikert ◽  
Matthias Tesche
Keyword(s):  
Cirrus Clouds ◽  
Radiation Budget ◽  
Cloud Type ◽  
The Earth ◽  
Spatial Coordinates ◽  
Cloud Optical Thickness ◽  
Ship Tracks ◽  
The Impact ◽  
Aircraft Data ◽  
Cloud Tracking

<p>Effects of aviation on the Earth’s radiation budget and climate related to CO<sub>2</sub> emissions and from the formation of linear contrails and contrail cirrus have been the focus of detailed studies. Aviation effects on existing cirrus clouds are much less investigated. Contrail formation in existing cirrus clouds has the potential to increase the cloud optical thickness (COT) of optically thin cirrus, which might result in a net cooling effect.</p><p>Spaceborne remote sensing generally provides the means for studying the impact of aviation on climate. However, only active instruments such as lidar or radar can be used to study the effect of contrails that form within existing cirrus clouds. For such an investigation, the location of an aircraft at a given time needs to be matched with information on cloud coverage, cloud type, cloud layer height, and COT as can be retrieved from spaceborne CALIPSO lidar data.</p><p>We have developed an algorithm to find intersections of aircraft flight tracks with satellite tracks. Besides the spatial coordinates, the time difference between the passing of the aircraft and the satellite at the intersection is monitored and relevant aircraft data and satellite recordings are retrieved at the intersection. The algorithm is highly adjustable so that it can be adapted for other applications such as investigation of ship tracks or cloud tracking. The new algorithm has been used to identify aircraft flying through cirrus clouds in remote regions of the Earth to study the effects of individual aircraft on existing cirrus.</p>

The impact of cloud inhomogeneities on the Earth radiation budget: the 14 October 1989 I.C.E. convective cloud case study

1994 ◽  
Vol 12 (2/3) ◽  
pp. 240-253 ◽  
Author(s):  
F. Parol ◽  
J. C. Buriez ◽  
D. Crétel ◽  
Y. Fouquart
Keyword(s):  
Aspect Ratio ◽  
Water Content ◽  
Liquid Water ◽  
Convective Cloud ◽  
Liquid Water Content ◽  
Radiation Budget ◽  
The Earth ◽  
Earth Radiation Budget ◽  
The Impact ◽  
Earth Radiation

Abstract. Through their multiple interactions with radiation, clouds have an important impact on the climate. Nonetheless, the simulation of clouds in climate models is still coarse. The present evolution of modeling tends to a more realistic representation of the liquid water content; thus the problem of its subgrid scale distribution is crucial. For a convective cloud field observed during ICE 89, Landsat TM data (resolution: 30m) have been analyzed in order to quantify the respective influences of both the horizontal distribution of liquid water content and cloud shape on the Earth radiation budget. The cloud field was found to be rather well-represented by a stochastic distribution of hemi-ellipsoidal clouds whose horizontal aspect ratio is close to 2 and whose vertical aspect ratio decreases as the cloud cell area increases. For that particular cloud field, neglecting the influence of the cloud shape leads to an over-estimate of the outgoing longwave flux; in the shortwave, it leads to an over-estimate of the reflected flux for high solar elevations but strongly depends on cloud cell orientations for low elevations. On the other hand, neglecting the influence of cloud size distribution leads to systematic over-estimate of their impact on the shortwave radiation whereas the effect is close to zero in the thermal range. The overall effect of the heterogeneities is estimated to be of the order of 10 W m-2 for the conditions of that Landsat picture (solar zenith angle 65°, cloud cover 70%); it might reach 40 W m-2 for an overhead sun and overcast cloud conditions.

scholarly journals The effect of optically thin cirrus clouds on solar radiation in Camagüey, Cuba

2011 ◽  
Vol 11 (3) ◽  
pp. 8777-8799
Author(s):  
B. Barja ◽  
J. C. Antuña
Keyword(s):  
Solar Radiation ◽  
Radiative Forcing ◽  
Near Infrared ◽  
Local Heating ◽  
Spectral Band ◽  
Solar Spectrum ◽  
Cirrus Clouds ◽  
Radiation Budget ◽  
Earth System ◽  
The Earth

Abstract. Cirrus clouds play a key role in the radiation budget of the Earth system. They are an important aspect in the climate system, as they interact with the atmospheric radiation field. They control both the solar radiation that reaches the Earth surface and the longwave radiation that leaves the Earth system. The feedback produced by cirrus clouds in climate is not well understood. Therefore it is necessary to improve the understanding and characterization of the radiative forcing of cirrus clouds. We analyze the effect of optically thin cirrus clouds characterized with the lidar technique in Camagüey, Cuba, on solar radiation, by numerical simulation. Nature and amplitude of the effect of cirrus clouds on solar radiation is evaluated. Cirrus clouds have a cooling effect in the solar spectrum at the Top of the Atmosphere (TOA) and at the surface (SFC). The daily mean value of solar cirrus cloud radiative forcing (SCRF) has an average value of −9.1 W m−2 at TOA and −5.6 W m−2 at SFC. The cirrus clouds also have a local heating effect on the atmospheric layer where they are located. Cirrus clouds have mean daily values of heating rates of 0.63 K day−1 with a range between 0.35 K day−1 and 1.24 K day−1. The principal effect is in the near infrared spectral band of the solar spectrum. There is a linear relation between SCRF and cirrus clouds optical depth (COD), with −30 W m−2 COD−1 and −26 W m−2 COD−1, values for the slopes of the fits at the TOA and SFC, respectively in the broadband solar spectrum. Also there is a relation between the solar zenith angle and cirrus clouds radiative forcing displayed in the diurnal cycle.

Trends in spectrally resolved OLR from 10 years of IASI measurements

2021 ◽  
Author(s):  
Simon Whitburn ◽  
Lieven Clarisse ◽  
Andy Delcloo ◽  
Steven Dewitte ◽  
Marie Bouillon ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Data Retrieval ◽  
Radiation Budget ◽  
Retrieval Algorithm ◽  
Earth Atmosphere ◽  
Clear Sky ◽  
The Earth ◽  
Atmosphere System ◽  
Spectrally Resolved ◽  
The Impact

<p>The Earth's Outgoing Longwave Radiation (OLR) is a key component in the study of climate. As part of the Earth's radiation budget, it reflects how the Earth-atmosphere system compensates the incoming solar radiation at the top of the atmosphere. At equilibrium, the two quantities compensate each other on average. Any variation of the climate drivers (e.g. greenhouse gases) causes an energy imbalance which leads to a climate response (e.g. surface temperature increase), with the effect of bringing the radiation budget back to equilibrium. Considerable improvements in our understanding of the Earth-atmosphere system and of its long-term changes have been achieved in the last four decades through the exploitation of measurements from dedicated broadband instruments. However, such instruments only provide spectrally integrated OLR over a broad spectral range and are therefore not well suited for tracking separately the impact of the different parameters affecting the OLR.</p><p>Better constraints can, in principle, be obtained from spectrally resolved OLR (i.e. the integrand of broadband OLR, in units of W m<sup>-2</sup> cm<sup>-1</sup>) derived from infrared hyperspectral sounders. Recently, a dedicated algorithm was developed to derive clear-sky spectrally resolved OLR from the Infrared Atmospheric Sounding Interferometer (IASI) at the 0.25 cm<sup>-1</sup> native spectral sampling of the L1C spectra (Whitburn et al. 2020).  Here, we analyze the changes in 10 years (2008-2017) of the IASI-derived OLR and we relate them to known changes in greenhouse gases concentrations (CO<sub>2</sub>, CH<sub>4</sub>, H<sub>2</sub>O, …) and climate phenomena activity such as El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO).</p><p>Whitburn, S., Clarisse, L., Bauduin, S., George, M., Hurtmans, D., Safieddine, S., Coheur, P. F., and Clerbaux, C. (2020). <strong>Spectrally Resolved Fuxes from IASI Data: Retrieval algorithm for Clear-Sky Measurements</strong>. Journal of Climate. doi: 10.1175/jcli-d-19-0523.1</p>

Spectrally resolved OLR from IASI measurements

2020 ◽  
Author(s):  
Simon Whitburn ◽  
Lieven Clarisse ◽  
Sophie Bauduin ◽  
Steven Dewitte ◽  
Maya George ◽  
...  
Keyword(s):  
Spectral Range ◽  
Climate Models ◽  
Southern Oscillation ◽  
Radiation Budget ◽  
Retrieval Algorithm ◽  
Distribution Models ◽  
Reanalysis Dataset ◽  
The Earth ◽  
Spectrally Resolved ◽  
The Impact

<p>The Earth’s Outgoing Longwave Radiation (OLR) is a key component in the study of climate feedbacks and processes. As part of the Earth’s radiation budget, it reflects how the Earth-atmosphere system compensates the incoming solar radiation at the top of the atmosphere. It can be retrieved from the radiance intensities measured by satellite sounders and integrated over all the zenith angles of observation. Since satellite instruments generally acquire the radiance at a limited number of viewing angle directions and because the radiance field is not isotropic, the conversion is however not straightforward. This problem is usually overcome by the use of empirical angular distribution models (ADMs) developed for different scene types that directly link the directional radiance measurement to the corresponding OLR.</p><p>OLR estimates from dedicated broadband instruments are available since the mid-1970s; however, such instruments only provide an integrated OLR estimate over a broad spectral range. They are therefore not well suited for tracking separately the impact of the different parameters affecting the OLR (including greenhouse gases), making it difficult to track down deficiencies in climate models. Currently, several hyperspectral instruments in space acquire radiances in the thermal infrared spectral range, and in principle, these should allow to better constrain the OLR. However, as these instruments were not specifically designed to measure the OLR, there are several challenges to overcome. Here we propose a new retrieval algorithm for the estimation of the spectrally resolved OLR from measurements made by the IASI sounder on board the Metop satellites. It is based on a set of spectrally resolved ADMs developed from synthetic spectra for a large selection of scene types associated with different states of the atmosphere and the surface. Atmospheric and surface parameters are derived from the Copernicus Atmosphere Monitoring Service (CAMS) reanalysis dataset and selected using a dissimilarity-based subset selection algorithm. These spectral ADMs are then used to convert the measured IASI radiances into spectral OLR.</p><p>We then evaluate how the IASI OLR compare with the CERES and the AIRS integrated and spectral OLR. We analyze the interannual variations in OLR over 10 years of IASI measurements for selected spectral channels using EOF analysis and we connect them with well-known climate phenomena such as El Niño-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Atlantic Multidecadal Oscillation (AMO).</p>

Impact of Dry Intrusions on the Marine Boundary Layer

2020 ◽  
Author(s):  
Eyal Ilotoviz ◽  
Shira Raveh-Rubin ◽  
Virendra Ghate
Keyword(s):  
Boundary Layer ◽  
Marine Boundary Layer ◽  
Weather Prediction ◽  
Lower Troposphere ◽  
Radiation Budget ◽  
Cold Fronts ◽  
The Earth ◽  
Strong Inversion ◽  
The Impact ◽  
Dry Intrusions

<p>Intrusions of dry air from the upper troposphere were recently suggested to reach the boundary layer and cause its significant deepening. Dry intrusions (DIs) are synoptic-scale slantwise descending airstreams from the midlatitude upper tropospheric jet towards the boundary layer at lower latitudes, thus acting as a circulation type potentially key for understanding boundary-layer cloud occurrence and regime transition. DIs occur mainly during winter over the mid-latitude oceanic storm track regions behind cold fronts trailing from cyclones. These regions are also home to marine boundary clouds that are an important component of the Earth’s radiation budget as they reflect much higher radiation back to the space compared to the ocean surface thereby cooling the Earth’s surface. Although subsidence is generally an inherent feature of the subtropical marine boundary layer, it is unclear how the marine boundary layer reacts to the transient, dynamically distinct DI, differently from the nominal subtropical subsidence resulting from the descending branch of Hadley circulation.</p><p>In this study we use the observations made at the Atmospheric Radiation Measurement (ARM) Eastern North Atlantic (ENA) site (39N, 28W) to characterize the impact of dry intrusions on Marine Boundary Layer (MBL) characteristics such as surface fluxes, thermodynamic stabilities and winds. Our analyses are based on measurements from the campaign: radiosondes, surface station data, polarimetric radar, lidar, radar wind profiler, ceilometer among others. Using all identified DI trajectories during the winters of 2016-2018 based on European Center for Medium-range Weather Forecasts (ECMWF) ERA Interim reanalysis data, we distinguish DI days from those before and following DIs, as well as periods with no DIs at all (with and without the occurrence of cold fronts for comparison). We find that during DI events the well-mixed MBL deepens and its vertical structure changes dramatically. Namely, the lower troposphere cools and dries substantially, inducing strong surface sensible and latent heat fluxes, while a strong inversion builds up at the MBL top, all affecting cloud occurrence. Finally, we used the numerical weather prediction (NWP) model COSMO at 2.2 km horizontal resolution to understand the detailed flows and structure in the MBL during DI events.</p>

scholarly journals Aerosol Characterization over a High Altitude Location in Central Himalayas

1970 ◽  
Vol 8 (3) ◽  
pp. 87-93
Author(s):  
P Pant
Keyword(s):  
High Altitude ◽  
Atmospheric Aerosols ◽  
Background Level ◽  
Radiation Budget ◽  
Cloud Droplets ◽  
Central Himalayas ◽  
The Earth ◽  
Suspended Particulate ◽  
Aerosol Parameters ◽  
The Impact

Our climate is strongly influenced by the manner in which solar radiation is absorbed and scattered in the Earth’s atmosphere. Atmospheric aerosols play an important role in modifying the radiation budget of the earth-atmosphere system. Aerosols have a direct impact on the atmosphere as they scatter and absorb solar and infrared radiations and indirectly affect the size distribution of cloud droplets. Hence, the knowledge of aerosols’ characteristics is the basic requirement for understanding the impact of aerosols on our environment. In order to delineate the optical and physical properties of aerosols, the collocated measurements of aerosols are carried out at Manora Peak (29.36 N; 79.45 E, altitude ~ 1960 meters), Nainital: a high altitude location in central Himalayas. Since the observing site is located geographically in the free troposphere, thus the aerosol measurements from such a region have the importance for providing a sort of background level of aerosol-parameters against which the impact of aerosol-loading from far-off low laying regions can be assessed. The retrieved parameters of aerosols at ARIES are comprised of aerosol optical depth, mass/number concentrations of composite aerosols, BC mass concentration, total suspended particulate matter, total columnar ozone and water vapor content, meteorological parameters, traces gases etc. The analyzed results have been summarized in the present talk. DOI: http://dx.doi.org/10.3126/jie.v8i3.5935 JIE 2011; 8(3): 87-93

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

scholarly journals The potentially hazardous NEA 2001 BB16

2019 ◽  
Vol 28 (1) ◽  
pp. 180-190
Author(s):  
Ireneusz Wlodarczyk
Keyword(s):  
Mean Value ◽  
Optical Observations ◽  
Uniform Sampling ◽  
The Earth ◽  
22Nd Century ◽  
Lyapunov Time ◽  
Gravitational Model ◽  
Calculated Probability ◽  
Potential Impact ◽  
The Impact

AbstractWe computed the impact solutions of the potentially dangerous Near Earth Asteroid (NEA) 2001 BB16 based on 47 optical observations from January 20.08316 UTC, 2001, through February 09.15740 UTC, 2016, and one radar observation from January 19.90347 UTC, 2016. We used two methods to sample the starting Line of Variation (LOV). First method, called thereafter LOV1, with the uniform sampling of the LOV parameter, out to LOV = 5 computing 3000 virtual asteroids (VAs) on both sides of the LOV, which gives 6001 VAs and propagated their orbits to JD2525000.5 TDT=February 12, 2201. We computed the non-gravitational parameterA2=(34.55±7.38)·10–14 au/d2 for nominal orbit of 2001 BB16 and possible impacts with the Earth until 2201. For potential impact in 2195 we find A2=20.0·10−14 au/d2. With a positive value of A2, 2001 BB16 can be prograde rotator. Moreover, we computed Lyapunov Time (LT) for 2001 BB16, which for all VAs, has a mean value of about 25 y. We showed that impact solutions, including the calculated probability of a possible collision of a 2001 BB16 asteroid with the Earth depends on how to calculate and take into account the appropriate gravitational model, including the number of perturbing massive asteroids. In some complicated cases, it may depend also on the number of clones calculated for a given sigma LOV1. The second method of computing the impact solutions, called thereafter LOV2, is based on a non-uniformly sampling of the LOV. We showed that different methods of sampling the LOV can give different impact solutions, but all computed dates of possible impacts of the asteroid 2001 BB16 with the Earth occur in accordance at the end of the 22nd century.

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