The Environmental and Geophysical Sciences (ENGEOS) Lab at Khalifa University is equipped with a comprehensive suite of state-of-the-art environmental monitoring instruments. These systems support a wide range of atmospheric and surface observations critical for research and operational applications.
Our instrumentation includes:
These instruments collectively enable high-quality observations of Radiation, Aerosols, Clouds, Fog, and Atmospheric Boundary Layer processes over the hyper-arid environment of the UAE.
In addition to the above instruments, Environmental and Geophysical Sciences (ENGEOS) laboratory and the Earth Science department have deployed Snow Ice Mass Balance (SIMBA), a special instrument to study ice in Antarctica. This is the first time scientists from any institution in the UAE have deployed operational instruments on the icy southern continent.
The RPG-HATPRO G5 is a state-of-the-art, ground-based passive microwave radiometer designed for high-resolution atmospheric profiling. It operates in two frequency bands:
The instrument features 14 channels (7 in each band) and measures brightness temperatures at up to 1-second temporal resolution. It supports two operating modes:
To retrieve atmospheric profiles from brightness temperature measurements, the radiative transfer equation is inverted using an artificial neural network (ANN) approach. The ANN was trained using radiosonde data from Abu Dhabi (UAE), Muscat (Oman), Dammam (Saudi Arabia), and ERA5 reanalysis data. Temperature and humidity profiles are retrieved every 5 minutes, from the surface up to 10 km above ground level, with vertical resolution better than 100 meters in the lower troposphere.
The system also provides estimates of cloud liquid water content using a relative humidity threshold method (95%). Key atmospheric quantities such as stability indices and boundary layer height can be derived from the retrieved profiles.
The system includes an Infrared Temperature Sensor (IRTS) operating in the 8鈥�14 渭m range, used to estimate cloud base height (CBH) and cloud liquid water. This sensor improves cloud transmittance assessments and enhances the accuracy of humidity profiles when combined with microwave observations.
The RPG-HATPRO is equipped with a blower and heating module to prevent dew or condensation during foggy conditions, making it ideally suited for fog monitoring and boundary layer studies.
Validation studies comparing MWR retrievals with radiosonde profiles from Abu Dhabi International Airport have been published in the Atmospheric Research听(濒颈苍办: ) journal.
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Figure 1. Microwave Radiometer 鈥� RPG-HATPRO (G5 Series).
The Vaisala CL61 is an advanced, dual-polarization ceilometer that goes beyond standard cloud base detection by offering detailed atmospheric profiling, including aerosol and cloud phase discrimination.
Key Specifications:
This high-end LiDAR-based ceilometer provides depolarization profiles, enabling precise identification of cloud phase (liquid vs. ice) and detection of aerosol types, including dust and volcanic ash. Such capabilities enhance situational awareness for both meteorological research and operational forecasting.
The depolarization feature is particularly valuable for:
Equipped with enhanced single-lens optics, the CL61 offers an improved signal-to-noise ratio, enabling high-resolution backscatter profiling even under challenging atmospheric conditions. Its rugged, automated design ensures reliable, unattended operation across all weather scenarios. The CL61 represents the latest in remote sensing instrumentation, combining advanced optics, polarization capability, and data-ready outputs in a cost-effective platform.
For more technical details, visit:
Figure 2. Dual-Polarization Ceilometer 鈥� Vaisala CL61.
The FM-120 Fog Monitor, developed by Droplet Measurement Technologies (DMT), is a highly sensitive optical instrument designed to measure the microphysical properties of fog. Widely used in fog research and weather modification programs, the FM-120 provides detailed observations of fog droplet size distribution and liquid water content (LWC).
Key Features:
The FM-120 determines droplet size by analyzing the angular distribution of laser light scattered by individual droplets. Using Mie theory, the instrument assumes the particles are spherical and composed of liquid water. Liquid Water Content (LWC) is derived by integrating over the measured size spectrum.
Its high temporal resolution and fine droplet classification make the FM-120 ideal for studying fog microphysics, evaluating visibility, and supporting model validation and forecasting tools.
听听听Applications:
For more information, refer to:
Figure 3. Fog Monitor 鈥� DMT (FM-120).
The AERONET (AErosol RObotic NETwork) Sun Photometer deployed at the ENGEOS Lab is part of NASA鈥檚 globally standardized network for ground-based aerosol monitoring and characterization. It provides long-term, high-quality observations of aerosol optical and microphysical properties that are essential for climate research, satellite product validation, and air quality assessments.
ENGEOS Lab operates a Cimel CE318-T Sun鈥揝ky鈥揕unar Multispectral Photometer, integrated into the NASA AERONET network.
AERONET is a global federation of ground-based remote sensing aerosol networks coordinated by NASA and PHOTONS (PHOtom茅trie pour le Traitement Op茅rationnel de Normalisation Satellitaire 鈥� University of Lille 1, CNES, and CNRS-INSU), supported by a wide range of international agencies, universities, and scientists.
Instrument Overview 鈥� Cimel CE318-T
The CE318-T is a next-generation, solar-powered photometer capable of measuring:
This upgraded version has been operational at ENGEOS Lab since March 2020, succeeding the original CE318 model installed in June 2012.
Technical Specifications:
By measuring sunlight attenuation and scattering at specific wavelengths, the instrument enables:
Sky radiance measurements at scattering angles 鈮�120掳 enable advanced inversion algorithms for aerosol characterization.
Applications at ENGEOS Lab:
The relevance of AERONET measurements in the UAE is well demonstrated in regional studies, including , which highlight the value of AOD and microphysical retrievals for advancing aerosol research in desert climates.
All data from the ENGEOS AERONET station are processed, quality-controlled, and publicly released by NASA Goddard Space Flight Center, accessible via the .
Figure 4. AERONET Sun Photometer.
The SPARTAN (Surface Particulate Matter Network) station at ENGEOS Lab is part of a global network designed to measure fine particulate matter (PM鈧�.鈧�) for improving satellite-based air quality estimates and enhancing our understanding of atmospheric aerosols . (). This initiative addresses critical gaps in global PM鈧�.鈧� coverage, providing publicly available data on:
These observations are vital for satellite product validation, climate and health impact assessments, and for air quality management strategies.
Filter Sampling Sensor
A second-generation automated air sampler that employs a high-precision dynamic cyclone inlet to collect:
Each cartridge collects data over a 9-day interval per filter, providing a total sampling duration of 54 days before replacement is required. The system operates autonomously and is designed for remote deployments with minimal maintenance.
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Integrating Nephelometer
A 3-wavelength optical nephelometer that measures:
Measurements are recorded every 15 seconds, and a built-in clean-air reference system performs regular baseline corrections in the field. The nephelometer also uses a cyclone inlet for dynamic size separation, allowing independent analysis of PM鈧�.鈧� and PM鈧佲個 optical properties.
Applications and Impact
The SPARTAN station at ENGEOS Lab plays a pivotal role in bridging satellite observations with ground-based aerosol measurements in the Middle East, contributing to global datasets used by researchers, policy-makers, and climate modelers worldwide.
The Campbell Scientific CS110 is a high-precision electric field mill designed for both lightning warning systems and atmospheric electricity research. At ENGEOS Lab, it is used to continuously monitor the vertical component of the atmospheric electric field at the Earth’s surface.
The CS110 system includes:
Key Features:
This robust compensation circuitry ensures accurate electric field measurements even under adverse environmental conditions, making the CS110 ideal for research in challenging climates like those of the UAE.
For more details on the CS110’s operation and its performance under various weather conditions, including fog events, please refer to our publication: Atmospheric Electric Field Variability During Foggy Conditions, .
Figure 6. Electric Field Mill.
The Empty Quarter Desert (Rub鈥� al Khali), one of the world鈥檚 most significant natural dust sources, frequently experiences intense dust storms caused by wind erosion. Despite its global relevance, in-situ observations from this hyper-arid region had been lacking until the launch of the Wind-blown Sand Experiment (WISE-UAE) in summer 2022.
Experiment site and Instrumentation:
The WISE Phase-1 deployment was established near Madinat Zayed (23.5761掳N, 53.7242掳E; elevation: 119 m), approximately 120 km southwest of Abu Dhabi. A 10-meter triangular micrometeorological tower was installed, equipped with horizontal booms at seven levels (0.4, 0.7, 1.25, 2.25, 3, 4, and 10 m above ground) to support:
A dedicated boom at 3 m height holds a 3-D sonic anemometer (see Figure 3a). The tower is stabilized using three guy wires, capable of withstanding wind speeds up to 60 m s鈦宦�.
Surface Radiation Energy Balance: To measure the four components of radiation fluxes (incoming/outgoing shortwave and longwave radiation), a Net Radiometer is mounted on a 2-meter tripod, located 4 meters south of the tower.
Saltation Monitoring: To investigate the initiation, intensity, and duration of saltation events, two instruments were deployed 10 meters from the tower:
Both sensors are mounted ~9 cm above the surface and log saltation counts (hits/second) every second using a CR1000X data logger.
To ensure data consistency, the soil surface around the sensors is regularly leveled after significant saltation events and during biweekly maintenance visits.
Erosion Flux Estimation: To quantify horizontal sand transport, Modified Wilson and Cooke (MWAC) traps were deployed:
Visibility Observations: Visibility is monitored using a SEN-TRY™ Visibility Sensor (SVS1), mounted at 2.5 meters on the main tower. The sensor estimates visibility by measuring scattered visible light from suspended dust and aerosol particles.
A detailed description of the WISE-UAE instrumentation and field measurements can be found in our publication in. he high-quality measurements collected during the WISE-UAE campaign have been used to validate reanalysis datasets and satellite-derived products. For more information, please refer to our article: 听.
Figure 7.听WInd-blown Sand Experiment-United Arab Emirates experiment setup. (a)听10听m meteorological tower showing all the instruments deployed on it. (b)听Net radiation (foreground) and electric field (background) sensors. (c)听Outdoor enclosures, with aerosol analyzers installed inside, and dust profiler. Ground sensors (d)听saltation sensors and (e)听soil temperature, soil moisture and ground heat flux.
The visibility sensor, Sentry™ SVS1, estimates the scattering of visible light by the atmosphere from which the extinction coefficient 渭 (amount of attenuation of a beam due to scattering and absorption by aerosols) is calculated. From this measurement, the visibility (v), a particularly useful quantity for fog-related applications, can be readily estimated. This is done separately for daytime and nighttime conditions through the equations below. Technical specifications of the visibility sensor refer our article, .
Figure 8.听Visibility sensor.
A portable weather station equipped with the WS501-UMB smart sensor and SW100 smart disdrometer from LUFFT is used to measure meteorological parameters at the site. The parameters measured by this weather station include air temperature, relative humidity, wind speed and direction, global shortwave radiation, precipitation type, and precipitation amount. The response of the LUFFT humidity sensor to higher humidity conditions is validated with other sensors both at coastal cite and inland locations. Please refer to our article for more details ().
Figure 9.听Portable weather station.
The Snow Ice Mass Balance Apparatus (SIMBA) is a state-of-the-art in situ system designed to monitor the temporal evolution of snow and sea ice thickness (SIT and ST) in polar environments. At ENGEOS Lab, we utilize this system to improve understanding of sea ice thermodynamics and validate remote sensing products.
Overview and Deployment
The SIMBA system deployed offshore from Mawson Station (67.5912掳S, 62.8563掳E) on 7 July 2022. It consists of a 5-meter thermistor string with sensors spaced every 2 cm, a barometer for surface pressure measurements, and an external air temperature sensor for monitoring near-surface conditions. The instrument remained fixed in place, capturing high-resolution data throughout the austral winters.
Measurement Technique
Each thermistor sensor is equipped with:
Heating cycles of 30 s and 120 s are applied once daily, while four unheated vertical temperature profiles are recorded each day. These data are used to:
The automatic detection algorithm distinguishes snow and ice based on temperature rise patterns:
SIMBA data enables us to monitor the dynamic evolution of sea ice in extreme environments, contributing to both climate science and operational forecasting.
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Figure 10.听SIMBA instrument prior to deployment.
