Airborne Passive Remote Sensing of Optical Thickness and Particle Effective Radius of Cirrus and Deep Convective Clouds

Within this Ph.D. thesis, the optical thickness and particle effective radius of cirrus and deep convective clouds (DCCs) are retrieved using passive remote sensing techniques. For this purpose, airborne and satellite measurements of spectral solar radiation combined with extensive radiative transfer simulations have been conducted. Data analyzed in this study were collected during the ML-CIRRUS and the ACRIDICON-CHUVA campaigns, which aimed to study natural and contrail cirrus over Europe and DCCs over the Amazon rainforest using the German High Altitude and Long Range Research Aircraft (HALO), respectively. During the campaigns, HALO was equipped with a comprehensive set of remote sensing and in situ instruments. In particular flights, closely collocated measurements with the overpasses of the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard of the Aqua satellite were carried out. A cirrus located above liquid water clouds and a DCC topped by an anvil cirrus are investigated. In general, the research framework can be divided into four parts. In the first part, the spectral upward radiances measured by the Spectral Modular Airborne Radiation Measurement System (SMART)-Albedometer aboard of HALO are compared with those measured by the MODIS. In the second part, a radiance ratio retrieval assuming a vertically homogeneous cloud is applied to obtain the cloud optical thickness and particle effective radius based on the measurements of SMART-Albedometer and MODIS. Multiple near-infrared wavelengths with different absorption characteristics are utilized in the retrieval in order to study the vertical structure of cloud particle sizes. In the third part, the retrieved cloud properties are compared with those derived from the MODIS cloud products. For the cirrus case, the retrieved values of particle effective radius are further compared to in situ data measured by the Cloud Combination Probe (CCP). To allow this comparison, a vertical weighting method is applied. Although the comparison results in a good agreement, retrievals using this conventional technique only provide information on cloud particle sizes from the upper layers, even if spectral measurements have been employed. The retrieved particle effective radius represents a vertically weighted value, where the upper cloud layers are weighted at most. In the fourth part, an extended technique based on Bayesian optimal estimation has been developed to obtain the full vertical profile of particle effective radius. For this purpose, a parameterization assuming the shape of the vertical profile with respect to a vertical coordinate within the cloud is applied. The information content of SMART-Albedometer measurements is analyzed to identify wavelengths that bring the most information pertaining to each retrieval parameter. The new retrieval technique is applied to the cirrus case to infer the profile of particle effective radius as a function of optical thickness. The comparison between the retrieved and the in situ profiles shows a good agreement with a deviation of about 5 % at the cloud top and increases to values of up to 15 % at the cloud base. The new retrieval technique has shown excellent skill in improving the study of the vertical profile of cloud microphysical properties, which can be applied in the future generation of airborne and satellite retrievals based on the measurements of passive remote sensing.:1. Introduction 2. Definitions 3. Measurements 4. Comparison of upward radiance 5. Retrieval of cloud optical thickness and particle effective radius 6. Comparison of cloud optical thickness and particle effective radius 7. Retrieval of the vertical profile of particle effective radius 8. Summary and conclusio

Vertical distribution of the particle phase in tropical deep convective clouds as derived from cloud-side reflected solar radiation measurements

Vertical profiles of cloud particle phase in tropical deep convective clouds (DCCs) were investigated using airborne solar spectral radiation data collected by the German High Altitude and Long Range Research Aircraft (HALO) during the ACRIDICON-CHUVA campaign, which was conducted over the Brazilian rainforest in September 2014. A phase discrimination retrieval based on imaging spectroradiometer measurements of DCC side spectral reflectivity was applied to clouds formed in different aerosol conditions. From the retrieval results the height of the mixedphase layer of the DCCs was determined. The retrieved profiles were compared with in situ measurements and satellite observations. It was found that the depth and vertical position of the mixed-phase layer can vary up to 900m for one single cloud scene. This variability is attributed to the different stages of cloud development in a scene. Clouds of mature or decaying stage are affected by falling ice particles resulting in lower levels of fully glaciated cloud layers compared to growing clouds. Comparing polluted and moderate aerosol conditions revealed a shift of the lower boundary of the mixed-phase layer from 5.6 +/- 0.2 km (269 K;moderate) to 6.2 +/- 0.3 km (267 K;polluted), and of the upper boundary from 6.8 +/- 0.2 km (263 K;moderate) to 7.4 +/- 0.4 km (259 K;polluted), as would be expected from theory

Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German–Brazilian cooperative aircraft campaign ACRIDICON–CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (global precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September–October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles ( 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable species in the UT. Subsequently, downward mixing and transport of upper tropospheric aerosol can be a source of particles to the PBL, where they increase in size by the condensation of biogenic volatile organic compound (BVOC) oxidation products. This may be an important source of aerosol particles for the Amazonian PBL, where aerosol nucleation and new particle formation have not been observed. We propose that this may have been the dominant process supplying secondary aerosol particles in the pristine atmosphere, making clouds the dominant control of both removal and production of atmospheric particles

Contributions from the DISC to accomplish the Aeolus mission objectives

The Aeolus Data Innovation and Science Cluster (DISC) supports the Aeolus mission with a wide range of activities from instrument and product quality monitoring over retrieval algorithm improvements to numerical weather prediction (NWP) impact assessments for wind and aerosols. The Aeolus DISC provides support to ESA, Cal/Val teams, numerical weather prediction (NWP) centers, and scientific users for instrument special operations and calibration, for the re-processing of Aeolus products from the past and through the provision of bi-annual updates of the L1A, L1B, L2A and L2B operational processors. The Aeolus DISC is coordinated by DLR with partners from ECMWF, KNMI, Météo-France, TROPOS, DoRIT, ABB, s&t, serco, OLA, Physics Solutions, IB Reissig and Les Myriades involving more than 40 scientists and engineers. The presentation will highlight the Aeolus DISC activities with a focus for the year 2021 and early 2022 since the last Aeolus workshop in November 2020. This covers the evolution of the instrument performance including investigations of the cause of the on-going signal loss and the achieved improvement via dedicated laser tests in 2021. In addition, refinements of algorithms and correction of the wind bias will be discussed - including a known remaining seasonal bias in October and March as encountered during the re-processing campaigns. Finally, the strategy for the on-going and future re-processing campaigns will be addressed to inform the scientific community about the availability and quality of the re-processed data products. The Aeolus mission has fully achieved its mission objectives including the unprecedented demonstration of direct-detection Doppler wind lidar technology and high-power laser operation in space in the ultraviolet spectral region over its planned full mission lifetime of 3 years and 3 months. Aeolus wind products have clearly demonstrated positive impact on forecasts using several NWP models. Since early 2020, and thus only 1.5 years after launch, the Aeolus wind products are used in operation at various NWP centers worldwide. This was achieved even despite the larger than expected wind random errors due to lower initial atmospheric signal levels and the observed signal losses during the operation of the first and second laser. In addition to this incredible success, first scientific studies demonstrated the use of Aeolus for atmospheric dynamics research in the stratosphere and for the analysis of aerosol transport. These achievements of the Aeolus mission and its success were only possible with the essential and critical contributions from the Aeolus DISC. This demonstrates the need and potential for setting up such scientific consortia covering a wide range of expertise from instrument, processors, and scientific use of products for Earth Explorer type missions. The invaluable experience gained by the Aeolus DISC during the more then 3 years of Aeolus mission in orbit (preceded by a period of 20 years before launch by a similar study team) is a pre-requisite for a successful preparation of an operational follow-on Aeolus-2 mission

Airborne Passive Remote Sensing of Optical Thickness and Particle Effective Radius of Cirrus and Deep Convective Clouds

Within this Ph.D. thesis, the optical thickness and particle effective radius of cirrus and deep convective clouds (DCCs) are retrieved using passive remote sensing techniques. For this purpose, airborne and satellite measurements of spectral solar radiation combined with extensive radiative transfer simulations have been conducted. Data analyzed in this study were collected during the ML-CIRRUS and the ACRIDICON-CHUVA campaigns, which aimed to study natural and contrail cirrus over Europe and DCCs over the Amazon rainforest using the German High Altitude and Long Range Research Aircraft (HALO), respectively. During the campaigns, HALO was equipped with a comprehensive set of remote sensing and in situ instruments. In particular flights, closely collocated measurements with the overpasses of the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard of the Aqua satellite were carried out. A cirrus located above liquid water clouds and a DCC topped by an anvil cirrus are investigated. In general, the research framework can be divided into four parts. In the first part, the spectral upward radiances measured by the Spectral Modular Airborne Radiation Measurement System (SMART)-Albedometer aboard of HALO are compared with those measured by the MODIS. In the second part, a radiance ratio retrieval assuming a vertically homogeneous cloud is applied to obtain the cloud optical thickness and particle effective radius based on the measurements of SMART-Albedometer and MODIS. Multiple near-infrared wavelengths with different absorption characteristics are utilized in the retrieval in order to study the vertical structure of cloud particle sizes. In the third part, the retrieved cloud properties are compared with those derived from the MODIS cloud products. For the cirrus case, the retrieved values of particle effective radius are further compared to in situ data measured by the Cloud Combination Probe (CCP). To allow this comparison, a vertical weighting method is applied. Although the comparison results in a good agreement, retrievals using this conventional technique only provide information on cloud particle sizes from the upper layers, even if spectral measurements have been employed. The retrieved particle effective radius represents a vertically weighted value, where the upper cloud layers are weighted at most. In the fourth part, an extended technique based on Bayesian optimal estimation has been developed to obtain the full vertical profile of particle effective radius. For this purpose, a parameterization assuming the shape of the vertical profile with respect to a vertical coordinate within the cloud is applied. The information content of SMART-Albedometer measurements is analyzed to identify wavelengths that bring the most information pertaining to each retrieval parameter. The new retrieval technique is applied to the cirrus case to infer the profile of particle effective radius as a function of optical thickness. The comparison between the retrieved and the in situ profiles shows a good agreement with a deviation of about 5 % at the cloud top and increases to values of up to 15 % at the cloud base. The new retrieval technique has shown excellent skill in improving the study of the vertical profile of cloud microphysical properties, which can be applied in the future generation of airborne and satellite retrievals based on the measurements of passive remote sensing.:1. Introduction 2. Definitions 3. Measurements 4. Comparison of upward radiance 5. Retrieval of cloud optical thickness and particle effective radius 6. Comparison of cloud optical thickness and particle effective radius 7. Retrieval of the vertical profile of particle effective radius 8. Summary and conclusio

Spectral upward radiance and retrieved cloud properties

The data contain spectral upward radiance at wavelengths = 645 nm, 1240 nm, and 1640 nm. For SMART, the measured radiances have been convoluted with the MODIS relative spectral response. Retrieval products, one cloud optical thickness (645 nm), and two particle effective radius (1240 nm and 1640 nm), are given. For more details, please contact the corresponding author

Developing of Total Suspended Sediment Model Using Landsat-8 Satellite Image and In-Situ Data at The Surabaya Coast, East Java, Indonesia

The decrease of coastal-water quality in the Surabaya coastal region can be recognized from the conceentration of Total Suspended Sediment(TSS ) . As a result we need a system for monitoring sediment concentration in the coastal region of Surabaya which regularly measures TSS. The principle to model and monitor TSSconcentration using remote sensing methods is by the integration of Landsat-8OLI satellites image processing using some ofTSS-models then those are analyzed for looking its suitability with TSS value direcly measured in the field ( in-situ measurement). The TSS value modeled from all algorithms validated usingcorrelation analysis and linear regression . The result shows that TSS model with the highest correlation value is TSS algorithm by Budiman (2004)with r value 0.991. Hence this algorithm can be used to investigate TSS-distribution which represent the coastal water quality of Surabaya with TSS value between 75 mg/L to 125 mg/L

Exploratory analysis of carbonaceous PM2.5 species in urban environments: Relationship with meteorological variables and satellite data

The carbonaceous chemical composition and mass concentration of particles with an aerodynamic diameter less than 2.5 μm (PM2.5), were analyzed, as well as their relationship with satellite data and meteorological variables. PM2.5 ground samples were collected at nine sampling sites with different land use in the metropolitan area of Córdoba city, during autumn and winter in 2018, and concentrations of organic carbon (OC) and elemental carbon (EC) were measured. The aerosol optical depth (AOD) was retrieved from the MODIS sensor, Aqua and Terra satellites. The AOD was validated using ground-based sun photometer data. Furthermore, the PM2.5 mass concentration and composition were simulated using multiple linear regression models, with the measured AOD and meteorological parameters as input variables. The data showed that PM2.5 mass concentrations varied in space throughout the city, indeed at four sampling sites, they exceeded the World Health Organization (WHO) daily guidelines. The OC and EC mass concentrations were moderate and low, respectively, in comparison with other cities in the world. PM2.5 concentrations were negatively associated with average planetary boundary layer (PBLav), dew point (DP) and AOD from Aqua satellite (AODa). The columnar average AODav did not correlate significantly with the ground-based PM2.5 measurements, however AODa was retained in a model to explain PM2.5 having a negative effect on particles. An effective carbon ratio (ECR) was calculated to estimate the radiative forcing of PM2.5 in a local scale. The results suggested an overall local radiative heating effect due to PM2.5.Fil: Amarillo, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Carreras, Hebe Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Krisna, Trismono. Sron Netherlands Institute For Space Research; Países Bajos. Universitat Leipzig; AlemaniaFil: Mignola, Marcos. Universidad Nacional de Córdoba. Facultad de Cs.exactas Físicas y Naturales. Cátedra de Química General; ArgentinaFil: Tavera Busso, Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Wendisch, Manfred. Universitat Leipzig; Alemani

Linear relationship between effective radius and precipitation water content near the top of convective clouds

Quantifying the precipitation within clouds is crucial for our understanding of the Earth's hydrological cycle. Using in situ measurements of cloud and rain properties over the Amazon Basin and Atlantic Ocean, we show here a linear relationship between the effective radius (re) and precipitation water content near the tops of convective clouds for different pollution states and temperature levels. Our results emphasize the role of re to determine both initiation and amount of precipitation