National Aeronautics and Space Administration

CATS: Measuring Clouds and Aerosols from the International Space Station Acknowledgements

CATS cats.gsfc.nasa.gov

The CATS instrument is funded by the International Space Station NASA Research Office with supplemental funding for research from NASA’s Earth Science Division. A special thanks is given to both parties and to the CATS science team for making this publication possible.

Content: Heather Hanson, Matt McGill, John Yorks Design: Debbi McLean Table of Contents

Clouds, Aerosols, and Earth’s Climate ...... 2

Measuring Clouds and Aerosols ...... 4

Mission Overview ...... 6

Instrument Overview ...... 8

Launch and Installation ...... 10

Benefits to Society and Technology ...... 12 Clouds, Aerosols, and Earth’s Climate

From space, streaks of white clouds can be seen swirling across Earth’s surface. In addition to clouds, other tiny solid and liquid particles, invis- Clouds and aerosols reflect ible to our eyes, called aerosols are also swirling around in Earth’s atmosphere. Aerosol particles about a quarter of the sun’s are both natural and man-made, and include energy back to space; however windblown dust from deserts, sea salt, smoke from wildfires, sulfurous particles from volcanic their impact on Earth’s global eruptions, and sulfurous and carbonaceous par- energy budget and climate is ticles produced by fossil fuel combustion. not yet fully understood due to Clouds and aerosols play an important role in complex interactions between Earth’s climate system because they reflect and absorb radiation from the sun differently. For clouds and aerosols. example, when the sun’s energy reaches the top of the atmosphere, clouds tend to reflect incoming sunlight, cooling Earth’s surface. However, clouds The interactions between clouds and aerosols are also tend to absorb heat emitted from the surface illustrated in this image, taken by retired astronaut and re-radiate it back down, warming Earth’s Chris Hadfield onboard the International Space surface. Therefore, the amount of warming or Station, showing contrails produced by aircraft (bright cooling is heavily dependent on the height, thick- streaks) over the ocean. In the absence of aircraft ness, and structure of clouds in the atmosphere. exhaust, natural aerosols are required to seed upper Aerosols—depending upon their size, type, and tropospheric ice cloud particles. Image credit: NASA/ location—can also either cool the surface, or Chris Hadfield

Why Do We Need Vertical Information? 12 km Aircraft Contrails Different types of clouds and 9 km aerosols can be found at varying Ash heights in the atmosphere and depending on their properties 6 km Clouds and location, they can have Smoke varying radiative effects on 3 km from Earth’s climate system. To Fires improve climate, weather, aerosol, and air quality models, scientists need to better understand these properties and cloud and aerosol vertical distribution in the atmosphere.

2 CATS: I Measuring Clouds and Aerosols from the International Space Station warm the atmosphere. In general, dark-colored aerosols such as black carbon from fossil fuel combustion absorb radiation, heating Earth’s at- mosphere, while bright-colored aerosols such as sulfates from volcanic eruptions reflect radiation, acting to cool Earth’s atmosphere.

Constantly in motion, different types of clouds and aerosols can be found at varying heights throughout the atmosphere and while they have Image credit: Sydney Oats relatively short lifetimes, they often have complex interactions when mixed together. For example, aerosol particles can affect the formation and properties of clouds (e.g., by activating early growth of cloud droplets and by changing the albedo, or reflectivity, of clouds). The relationship between clouds and aerosols and the resulting influence on Earth’s climate is therefore multi- faceted, with impacts on Earth’s energy balance, hydrologic cycle, and atmospheric circulation.

Although most aerosols reflect sunlight, some also Aerosols, both natural and man-made, also affect Image credit: US Forest Service Gila National absorb it. An aerosol’s effect on light depends air quality. Near Earth’s surface, aerosol particles Forest/Kari Greer primarily on the composition and color of the are pollutants that can exacerbate poor air quality particles. Broadly speaking, bright-colored or conditions harmful to our health. For example, translucent particles tend to reflect radiation in all small aerosols can enter the human lungs and directions and back towards space. Darker aerosols blood, where they can cause respiratory issues can absorb significant amounts of light. Pure sulfates and even heart attacks. Higher in the atmosphere, and nitrates reflect nearly all radiation they encounter, aerosols ejected from volcanoes can disrupt air cooling the atmosphere. Black carbon, in contrast, absorbs radiation readily, warming the atmosphere traffic—as was dramatically demonstrated during but also shading the surface. Image credit: NASA the 2010 eruption of the Eyjafjallajökull volcano in Iceland, which caused an estimated $1.7 bil-

lion dollar loss for the airline industry. Image credit: Thawt Hawthje To predict changes in Earth’s climate and air quality scientists use measurements of clouds and aerosols to simulate forecasts using com- puter models. However, due to the complexities mentioned here, there are large uncertainties in Factory the way models handle clouds and aerosols and Emissions Vehicle their radiative properties. Therefore, obtaining Exhaust a better understanding of cloud and aerosol coverage, distribution, and type throughout all vertical layers of the atmosphere is critical for understanding and predicting Earth’s climate as Image credit: Bojan Rantaša well as air quality conditions. Some aerosols close to the surface, such as dust, smoke from wildfires, and harmful pollutants, can cause Composite image created from photographs by: Patrick Byrne, Carolyn Conner, air quality issues and impact Peggy Davis, Daniel Fogg, John Newman, Cyrus Reed, and Gayle Trautman human health.

CATS: I Measuring Clouds and Aerosols from the International Space Station 3 Measuring Clouds and Aerosols

Today scientists use an array of satellite, aircraft, infer other properties, such as the composition of and ground-based instruments to measure and clouds, the abundance and sizes of aerosols, and monitor clouds and aerosols. For many years the altitudes of cloud and aerosol layers. scientists have observed clouds and aerosols using passive remote sensors that measure the amount In 1999 NASA developed an airborne lidar sys- of radiation reflected and emitted by Earth. These tem called the Cloud Physics Lidar, or CPL, for sensors are important for providing information use on the high-altitude ER-2 aircraft. Still used about aerosol and cloud concentrations over large areas but are not commonly used for distin- guishing differences in height or type. To better observe the vertical structure of clouds and aero- sols, scientists turn to another tool: active remote sensing instruments, which include lidar.

Lidar works by using a laser to send a pulse of energy through the atmosphere towards a distant object (i.e., a cloud droplet or aerosol particle). Active lidar remote sensing Once the energy reaches the object, some of instruments provide information the energy is reflected back to the lidar receiver. about the three-dimensional Scientists can calculate the distance between the The primary capability for CATS was adapted from distribution of clouds and the CPL design. Pictured here, the Cloud Physics lidar instrument and the object (i.e., its location aerosols by emitting a laser Lidar was designed and built by scientists and in the atmosphere) based on the time it takes the pulse of light and measuring the engineers at NASA’s Goddard Space Flight Center. elapsed time of the return signal. reflected energy to return to the receiver. The in- Image credit: NASA Image credit: NASA tensity of this return pulse also allows scientists to

CPL 532 nm Attenuated Backscatter Profiles 20 1 x 10-5

-6 15 8 x 10 ) 6 x 10-6 -1 10 sr 4 x 10-6 -1 (m

altitude (km) 5 2 x 10-6

0 0 attenuated backscatter 7:00 17:20 17:42 18:03 18:24 18:46 19:07 19:28 19:49 20:11 20:32 Flight Time (hours, UTC) Saharan dust subvisual cirrus cirrus boundary layer aerosol low-level cumulus convective clouds This vertical profile from the airborne CPL lidar instrument shows different cloud and aerosol types and concentrations at various heights in the atmosphere. Measurements of the vertical distribution of clouds and aerosols are useful in many diverse scientific disciplines such as climate studies, weather research and prediction, atmospheric geochemistry, aerosol impacts on the biosphere, as well as satellite and model calibration and validation. Image credit: NASA

4 CATS: I Measuring Clouds and Aerosols from the International Space Station today, the CPL uses a high-repetition-rate laser extend the CALIPSO data record for continuity to provide atmospheric profile measurements of of lidar climate observations. Ideally, CALIPSO clouds and aerosols. The ER-2 typically flies at will still be operational when CATS becomes approximately 65,000 feet (20 kilometers) above active allowing for a period of intercomparison the Earth’s surface, which allows the instruments between CATS and CALIPSO data, and likewise onboard to function as spaceborne instrument CATS would be operational long enough to get simulators. While the CPL provides valuable data EarthCARE up and running. to the research community and has done so for many years, it does not provide continuous, near- global coverage like satellites can.

In 2006 NASA launched the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observa- tions, or CALIPSO, spacecraft—a joint mission between NASA and the French Centre National d’Études Spatiales (CNES). Similar to CPL’s lidar, CALIPSO carries a lidar that provides vertical distributions and properties of clouds and aerosols along a flight track. However, the CALIPSO lidar has exceeded its three-year prime mission and has been using its backup laser since 2009.

It is critical to continue the measurement To study aerosols, researchers from NASA’s Global Modeling and Assimilation Office ran a capabilities of CALIPSO to better assess the simulation of the atmosphere using the Goddard Earth Observing System Model Version 5, or climatological impacts of clouds and aerosols GEOS-5, that captured how winds transport aerosols around the world. This image represents through the use of computer models. To do so, how sea salt (blue) and dust (orange) swirl inside cyclones, sulfates (white) stream from these measurements are required over time scales surface emissions and volcanoes, and carbon (green) bursts from fires. Such simulations that are much longer (~20-30 years) than typical allow scientists to better understand how these tiny particulates travel in the atmosphere and mission lifetimes (~5-10 years). The next satellite influence weather and climate. Image credit: NASA’s Scientific Visualization Studio mission with a lidar onboard is scheduled to launch in 2018—a joint European and Japanese spacecraft called the Earth Clouds, Aerosols, and Radiation Explorer, or EarthCARE. NASA also plans to launch the Aerosols, Clouds, and Ecosystems (ACE) mission; however, it is Launch December 2014 planned for a post-2020 launch date. As a result, 6 month requirement 3 year goal HSRL/UV the cloud and aerosol research community faces demonstration a significant data gap in terms of continuing the for ACE Mission CALIPSO data record. 2005 2010 2015 2020

However, a unique opportunity to fill the potential data gap presented itself in 2011 when the International Space Station (ISS) NASA ACE Research Office offered scientists at NASA’s God- Bridge data gap Space- between CALIPSO based dard Space Flight Center a mounting location Launched in 2006 and EarthCARE HSRL likely to mission to onboard the space station for a new lidar instru- Using 2nd laser launch in 2018 launch since 2009 2020s ment called the Clouds and Aerosol Transport System, or CATS. Scheduled for launch in The CATS mission will help extend the CALIPSO data record to ensure continuity of lidar December 2014, CATS will serve as a “bridge” climate observations. Image credit: NASA between CALIPSO and EarthCARE, helping to

CATS: I Measuring Clouds and Aerosols from the International Space Station 5 Mission Overview

Several aspects of CATS make the mission and 435 kilometers (~270 miles) above Earth’s extraordinarily unique. To start, the CATS surface at a 51-degree inclination with nearly a instrument was to be designed and built in only three-day repeat cycle. This unique orbit path two years and on a much smaller budget than tra- will allow the CATS instrument to observe the This mission provides ditional satellite missions. Given this two-year de- same spot on Earth at different times each day, a unique opportunity to sign time—which is very short compared to most providing far more comprehensive coverage of spaceborne missions—scientists and engineers the tropics and mid-latitudes (between 51.6 demonstrate ISS-based at NASA’s Goddard Space Flight Center needed degrees north and south latitude) than sun-syn- operational science to work quickly. To do so they leveraged existing chronous orbiting satellites (like CALIPSO) that instrument designs from the CPL and Airborne observe the same Earth scene at the same local capabilities as well as an Cloud-Aerosol Transport System, or ACATS, time each day. This will allow scientists to, for opportunity to demonstrate and used commercial parts where possible. In the first time ever, study diurnal (day-to-night) particular, Fibertek, Inc. provided the laser units changes in cloud and aerosol effects from space. new technologies for future and the avionics/communications package and Earth science missions (e.g., Design Interface, Inc. provided mechanical CATS will also provide a continuous stream of design services. data from the ISS and, unlike CALIPSO and NASA’s ACE mission) at a other Earth-observing satellites, does not rely on relatively low cost. Designed to operate for at least six months— ground stations to downlink data once or twice with a goal of three years, and the possibility to daily. In addition, this mission provides a unique operate as long as five years—CATS will provide opportunity to demonstrate ISS-based operational vertical profiles of cloud and aerosol proper- science capabilities as well as an opportunity to ties at three wavelengths (1064, 532, and 355 demonstrate new technologies for future Earth nanometers). Onboard the space station, CATS science missions (e.g., NASA’s ACE mission) at a will orbit between 375 kilometers (~230 miles) relatively low cost.

Artist’s rendition of CATS collecting a swath of data from the ISS. Image credit: NASA

6 CATS: I Measuring Clouds and Aerosols from the International Space Station Science Goals

1. CATS will help extend the global lidar data record for continuity of climate observations. In particular, CATS will:

• Continue the data record of vertical profiles of cloud/aerosol properties;

• Improve our understand- ing of aerosol and cloud properties and interac- tions; and

• Improve model estimates of climate forcing and predictions of future climate change.

2. Data from CATS will improve operational aerosol forecasting programs. In particular, the data will: Onboard the ISS, CATS will provide a continuous stream of data that can be used for research applications such as studying cloud and aerosol properties and detecting wildfires. CATS will also provide data that can be • Improve model perfor- used in near real-time for several forecasting applications including plume tracking and air quality monitoring. mance through assimila- Image credit: NASA tion of near-real-time cloud/aerosol data; Due to the unique orbit path of the ISS, • Enhance air quality moni- CATS will observe the toring and prediction same spot on Earth at capabilities by providing different times each day. vertical profiles of pollut- In addition, the low- ants; and inclination orbit permits extensive measurements • Improve strategic and over aerosol source and hazard-warning capabili- aerosol transport regions. ties of events in near real- Image credit: NASA time (e.g., dust storms and volcanic eruptions). The space station CATS-ISS Monthly Coverage: September 2012 (0-24 hrs local time) revisits the same latitude 60 3. The CATS payload will at slightly different local 20 serve as a technology demon- times on each orbit. 18 30 16 stration for future space- In general, this means 14 based lidar missions. In it covers all points on 12 particular, the payload will: Earth’s surface between 0 10 51.6 degrees north 8 6 • Demonstrate High and south latitude at all -30 4 Latitude (degrees)

Approx. Number of Spectral Resolution Lidar times of day in roughly 2 Overpasses (max 44) (HSRL) aerosol retrievals two months. Image -60 credit: NASA -180 -120 -60 0 60 120 180 and 355 nanometer (ul- traviolet) data for future mission development.

CATS: I Measuring Clouds and Aerosols from the International Space Station 7 Instrument Overview

The CATS instrument can operate in three dif- for future missions (e.g., ACE). Mode 1, also Mode 1: Multi-Beam ferent modes and uses two high-repetition-rate referred to as the multi-beam mode, splits the Backscatter: 532, 1064 nm lasers. Data from CATS will be used to derive a energy from the first laser into two wavelengths No HSRL Depolarization: 532, 1064 nm variety of properties of cloud and aerosol that represent near infrared radiation (1064 Science Goals: 1, 2 layers including: backscatter, layer TRANSPORT SYSTEMnanometers) and visible light (532 height, layer thickness, ex- nanometers)—similar to STEM tinction (how much light CLOUDCL - AEROSOL CALIPSO. This two-wave- is lost due to scattering length mode is necessary and absorption), optical for determining layer type depth (the total loss of A (i.e., cloud and aerosol light through a layer), T composition) since dif- and at least a coarse C ferent particles reflect discrimination of S the two wavelengths aerosol and cloud type differently. For example, (e.g., smoke, dust, pol- water particles tend to lution, water droplet, ice scatter more “light” at Mode 2: HSRL Demo crystal) using a technique 1064 nanometers than at 532 Backscatter: 532, 1064 nm called depolarization-based nanometers, while aerosols tend HSRL: 532 nm NASA GSFC - ISS National Laboratory Depolarization: 1064 nm discrimination of particle type. to scatter more at 532 nanome- Science Goals: 1, 3 ters than at 1064 nanometers. Ice CATS will operate in Mode 1 for the major- particles, on the other hand, tend to scatter the ity of the mission, as Modes 2 and 3 will be same amount of light at both wavelengths. used intermittently to test new technologies

Mode 3: UV Demo Backscatter: 355, 532, 1064 nm No HSRL Depolarization: 532,1064 nm Science Goals: 1, 2, 3

Engineers at NASA’s Goddard Space Flight Center assemble the CATS payload inside the cleanroom. The Image credit: NASA instrument payload weighs 494 kilograms (~1100 pounds). Image credit: NASA

8 CATS: I Measuring Clouds and Aerosols from the International Space Station Primary Power Supply Other Detector Boxes

Payload Interface Unit (PIU) HSRL Detector Box Telescope

Current climate models

Laser 1 do not accurately predict Telescope Cover the vertical distribution of clouds and aerosols or their

Instrument parts are labeled in this diagram of the CATS payload. (Note, Laser 2 does not layer type. To reduce these appear in this view and is therefore not labeled in this image.) Image credit: NASA uncertainties, scientists will use lidar data from CATS to initialize forecast models, Determining layer type is important because dif- precise measurements. In particular, Mode 2 will ferent clouds and aerosols have different radiative provide better estimates of extinction, which subsequently producing properties that impact Earth’s radiative balance is extremely important for model applications more accurate results. in a variety of ways. Current climate models do since it is an important variable in determining not accurately predict the vertical distribution of the radiative effects of clouds and aerosols on the clouds and aerosols or their layer type. To reduce climate system. these uncertainties, scientists will use lidar data from CATS to initialize forecast models, sub- Mode 3 also uses the second laser and in addi- sequently producing more accurate results. Ad- tion to operating at 1064 and 532 nanometers, ditionally, determining layer type is important for adds a third wavelength at 355 nanometers. forecasting air quality conditions. In particular, The shorter wavelength of 355 nanometers lies aerosol types that consist of small particles, such in the ultraviolet region of the electromagnetic as sulfates and carbons, are more dangerous to spectrum and will therefore interact with par- human health than larger aerosols such as dust. ticles differently than 1064 and 532 nanometer wavelengths. Scientists are eager to learn more Operational Mode 2 uses the second laser and about the use of this new wavelength and look will demonstrate a new technology called High forward to what this new capability might mean Spectral Resolution Lidar (HSRL). This new for future space-based lidar mission develop- technique uses a narrower wavelength interval ment, especially the EarthCARE mission. at 1064 and 532 nanometers to provide more

CATS: I Measuring Clouds and Aerosols from the International Space Station 9 Image credit: NASA/Tony Gray and Tim Powers Launch andInstallation SpaceX Dragoncargospacecraft. Imagecredit: NASA the Space Station Remote Manipulator System, Arobotic armonthespacestationcalled berthed. station, theDragon spacecraftwillberobotically fly ontheJEM-EF. Whenit reaches thespace EF)—the firstNASA-developed payloadtoever Experiment Module –Exposed Facility (JEM- on theInternational Space Station’s Japanese willbeinstalled Once launched,theinstrument for installationtotheISS. heatersfrom launchuntilitisremovedsurvival whichwillprovidetrunk, power tothepayload’s mounted insidetheDragon’s unpressurized the CATS willbestrategically instrument atop aFalcon-9 launchvehicle. Prior tolaunch, consists ofaDragon cargospacecraftmounted mission totheISSinDecember 2014.SpaceX-5 on theSpaceX CargoResupply-5, orSpaceX-5, The CATS isscheduledtolaunch instrument 10

CATS: IMeasuringClouds andAerosols from SpaceStation the International (i.e., a spacewalk). (i.e., aspacewalk). reasons suchasduringanextra-vehicular activity needstobeturnedoffforsafety the instrument tinuously aspossible,except duringperiods when intended tooperatecontinuously, orasnear-con- commands. Onboard thespacestation,CATS is Goddard Space Flight Centerusingreal-time conducted through ground control atNASA’s to theJEM-EF, allonboard operationswillbe issuccessfullyattached Once the instrument totheJEM-EF.attach theinstrument the Japan Aerospace Exploration Agencythatwill Manipulator System, orJEMRMS,controlled by called theJapanese Experiment Module Remote andpassittoasecondrobotic arm the trunk from NASA, willthenextracttheinstrument or SSRMS,controlled by ground controllers at Onboard the space station, CATS is intended to operate continuously, or as near- continuously as possible, except during periods when the instrument needs to be turned off for safety reasons such as during an extra-vehicular activity (i.e., a spacewalk).

Prior to launch, the CATS instrument will be strategically mounted inside the Dragon trunk on SpaceX. Image courtesy: SpaceX

Pictured here, CATS will be fully exposed to the space environment once mounted on the JEM-EF. Image credit: NASA edit: NASA

CATS: I Measuring Clouds and Aerosols from the International Space Station 11 Image cr Benefits to Society and Technology

In this image from the Sea- Air, or the atmosphere, is essential for life on Provided here are just a few examples of recent Earth. It protects life by absorbing ultraviolet events where air quality impacted daily life. Data Viewing Wide Field-of-View solar radiation, warming the surface through from CATS can make a difference in predict- Sensor (SeaWiFS), a large heat retention (greenhouse effect), and reducing ing, responding to, and mitigating the impact of temperature extremes between day and night. In similar events in the future. dust storm moves across addition to protecting us, the quality of Earth’s Volcanic Eruptions. the Atlantic Ocean off the air, or air quality, impacts the health of all living • On June 4, 2011, things from humans to plants. the Puyehue-Cordón Caulle volcano in coast of Africa on February Chile experienced its first major eruption 26, 2000. Dust storms such Air quality fluctuates from day to day for a in decades. The volcano sent an ash plume number of reasons. Most obviously, air qual- eastward, disrupting air traffic, threatening as this one are common in ity changes if more pollutants are put into the water supplies, and even dropping golf ball- this area and can lift dust a atmosphere. Large events such as dust storms, sized pumice on parts of Argentina. Volcanic wildfires, volcanic eruptions, and days with high- ash (very different from ash from ordinary few kilometers high in the energy demands can dramatically influence air fires) is made of tiny, jagged particles of rock atmosphere, where it inter- quality and impact human health and activities. and glass that are very abrasive and slightly acts with clouds—called the corrosive, and can even conduct electric- Currently, scientists get a broad picture of air ity when wet. In addition to disrupting air Saharan Air Layer. Scientists quality conditions in the atmosphere and gener- traffic, it can irritate respiratory systems, coat ate air quality forecasts by combining satellite, at NASA are studying these vegetation and leave it inedible to wildlife aircraft, and ground-based data with sophisticated and livestock, and destroy machinery. waves of westward-traveling computer models. However, most datasets do not provide information about the vertical structure of • Dust Storms. In mid-October 2012, the dust to better understand clouds and aerosols and their layer type. Incorpo- Great Plains of the United States endured their impact on tropical rating the near real-time vertical data that CATS a widespread dust storm due to months of storm and hurricane forma- will produce is expected to improve our ability to drought and searing heat. Severe winds blew track different cloud and aerosol types at all layers soil and sediment across hundreds of miles tion. Credit: NASA/SeaWiFS of the atmosphere. These datasets will be used to causing near blackout conditions in some Ocean Color Team improve strategic and hazard-warning capabilities places. Authorities had to close portions of of events in near real-time (e.g., plume tracking Interstate 35 in Kansas and Oklahoma, as for dust storms, volcanic eruptions, and wildfires), well as Interstate 80 in Wyoming, due to which ultimately impact our daily lives. accidents and poor visibility. More common

Coarse Particulate Matter (PM ) Human Hair 10 Particles 10 µm in diameter, (e.g., Particles in PM Coarse dust, pollen, and mold) the Air 10 Fine, airborne particulate matter (PM) that is particles enhaled are filtered by smaller than 2.5 microns (about one thirtieth Fine Particulate Matter the nose and the width of a human hair) is considered (PM ) Particles 2.5 µm in 2.5 mouth diameter or smaller, (e.g., dangerous because it is small enough to sulfates and carbon) enter the passages of the human lungs. Most PM Fine particles travel PM aerosol particles come from the burning Magnified 2.5 2.5 Human Hair to the lungs, aggravating of fossil fuels and biomass (wood fires and asthma, causing difficulty 50 to 70 µm in agricultural burning). diameter breathing and decreased lung function. Image adapted from EPA and SCMP

12 CATS: I Measuring Clouds and Aerosols from the International Space Station Volcanic Eruptions are dust storms that originate over large deserts such as the Gobi and Taklimakan. Puyehue-Cordón Caulle This image shows the volcanic plume coming from Puyehue-Cordón Caulle in • Pollution Outbreaks. Residents of Beijing Chile on June 4, 2011 shortly after the and many other cities in China are used to eruption began. The brown ash plume reaches high above the clouds and casts having their lives impacted by poor air qual- a shadow towards the southeast. Along ity. Like many times before, a thick layer of the leading edge of the plume, it appears haze blanketed the North China Plain on that heavier material has fallen out of the ash cloud, while finer particles remain October 9, 2014. That same day, measure- suspended in the atmosphere. Credit: ments from ground-based sensors at the NASA’s Earth Observatory

U.S. Consulate in Beijing reported PM2.5 20 km measurements of 334 micrograms per cubic N meter of air. The World Health Organization Dust Storms

considers PM2.5 to be safe when it is below 25 micrograms per cubic meter of air. NASA’s Aqua satellite captured this natural-color image of dust storms in the • Forest Fires. Smoke from the California prairies of the United States on October Rim Fire in September 2013 choked Yo- 18, 2012. Gale-force northwest winds blew semite National Park during the busy Labor Dust along the western edge of a storm system that stretched from the Canadian border to Day weekend. The fire started on August Kansas. High winds carried dust and dirt 17, 2013, and was the third largest wildfire as much as 900 to 1200 meters (3000 to in California’s history. The smoke caused 4000 feet) into the atmosphere, according to local weather reports. Credit: NASA’s poor air quality from Yosemite National Park Earth Observatory to the San Joaquin Valley and people were 100 km advised to avoid strenuous outdoor activity N or to remain indoors since smoke can irritate Pollution Outbreaks the eyes and respiratory system and aggravate chronic heart and lung disease. Fog NASA’s Terra satellite acquired this In addition to anticipated improvements to opera- natural-color image of northeastern China on October 9, 2014. The image tional forecasting programs, CATS will also dem- shows extensive haze, low clouds, and onstrate new technologies for observing and mea- fog over the region. The haze obscured suring clouds and aerosols. The HSRL technique Haze Bohai many features usually visible in satellite Sea imagery of the area, including China’s (described in the Instrument Overview section) is largest city, Beijing. Credit: NASA’s expected to provide more precise measurements Earth Observatory from space than ever before. Scientists will also get Clouds a first-ever, space-based look at cloud and aerosol 100 km retrievals in the ultraviolet—355 nanometers. N Forest Fires In summary, the CATS mission seeks to build on the CALIPSO data record, provide observational Officially contained on Thursday, lidar data to improve research and operational October 24, 2013, the California Rim modeling programs, and demonstrate new lidar Clouds Fire burned approximately 257,314 retrievals of clouds and aerosols from space. These acres (~402 square miles)—the largest Yosemite wildfire on record in the Sierra Nevada. technologies and the science gained from the CATS Valley NASA’s Aqua satellite acquired this mission will be used to design future missions that view of the fire on August 31, 2013. The will study clouds and aerosols and their affects on California smoke is brown and smooth in texture Smoke compared to the bright white clouds. Earth’s climate and air quality for years to come. Credit: NASA’s Earth Observatory

Data from CATS will be freely available at 20 km cats.gsfc.nasa.gov. N

CATS: I Measuring Clouds and Aerosols from the International Space Station 13 National Aeronautics and Space Administration www.nasa.gov

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