# Presentation: 825762

## THE ARM UAV Program: 

- Past, Present and Future

- Greg M. McFarquhar1 and Will Bolton2
- 1University of Illinois, Urbana, IL
- 2Sandia National Laboratories, Livermore, CA

-                             Funded by ARM UAV Program

## Overview of ARM UAV Program

- Instruments for Cloud Research
- New Science Issues UAVs can address

## ARM UAV Program Objectives

**The ARM-UAV Program was established by DOE to**
**address the largest source of uncertainty in global warming:**
**the interaction of clouds and solar/thermal energy**
**support the climate change community with valuable data sets**
**develop measurement techniques and instruments suitable for use with the new class of high altitude, long endurance UAVs**
**demonstrate these instruments and measurement techniques in field measurement campaigns**

## ARM-UAV has conducted ten major field campaigns

***Field Campaigns to date:***
**Fall 1993, Edwards AFB, CA**
**Spring 1994, Northern OK**
**Fall 1995, Northern OK**
**Spring 1996, Northern OK**
**Fall 1996, Northern OK**
**Fall 1997, Northern OK**
**Spring 1999, PMRF Kauai, HI**
**Summer 1999, Monterey, CA**
**Winter 2000, Northern OK**
**Fall 2002, Northern OK**

**GA-ASI “GNAT 750”**
**(F93, S94)**

**Grob “Egrett”**
**(F95, S96)**

**GA-ASI “Altus I” (F96, F97)**

**GA-ASI “Altus II”**
**(Su99)**

**Twin Otter**
**(F93, S94, F95, S96, F96,**
**F97, Sp99, Su99, W00)**

## Currently using Proteus, available from Scaled Composites, in piloted mode; flies to over 50 kft; 6900 kg payload; ~20 h duration

## Current Suite of Instruments

- Passive remote sensing (14 instruments)
- Active remote sensing (2 instruments)
- In-situ Microphysics (4 instruments)
- Atmospheric State (5 instruments)

## Proteus Payload  - Passive Remote Sensing

** ****Broadband Radiometers  Package **(BRP)
** **CM-22 pyranometers, 0.3 – 4um  (zenith level, zenith fixed, nadir, nadir covered)
-  CG-4  pyrgeometers,  4 – 40 um  (zenith level, nadir, nadir covered)
** ****Spectral Radiance Package **(SRP)
-  nadir mounted, NFOV
-  VIS 0.38-1 um, 2nm res,
-  A-Band 0.75-0.85 um, 0.07nm res
-  NIR 1.3-1.5 um, 2nm res
** ****Solar Spectral Flux Radiometer **(SSFR)
-  nadir & zenith,  hemispheric FOV
-  300–1700 nm** **
** ****The Diffuse Field Camera **(DFC)
-  VIS: 1300 x 1030 pixels x 12 bit, 645 nm center with 50 nm total bandpass
-  NIR: 320 X 256  pixels x 12 bit, 1610 nm center with 60 nm total bandpass
**Scanning High-Resolution Interferometer Sounder **(S-HIS)
-  scanning interferometer,** **high spectral resolution (0.5 cm-1)
-  Spectral Coverage** **between 3.3 and 18.0 μm

**Proteus Payload  -** **Passive Remote Sensing**

## Stabilized Platform for High Altitude Remote Sensing

**Stabilized Platform for High Altitude Remote Sensing**

- Location of Stabilized platform

-  **First flown in 2002**
** ****Level to ±.02****o**
** ****Improved data quality and** **data range** (±2 to  ±5o)
_** **__**Significantly reduces post processing time**_

## Stabilized platform roll

- less than ±0.02o

- Aircraft roll ±3o

## Platform was stabilized until 18 hours

## Proteus Payload - Active Remote Sensing

**Proteus Payload - Active Remote Sensing**

-  **95 GHz Compact Millimeter Wave Radar** (CMR)** **
- sensitivity of –42 dBZ at 1 km
** ****Cloud Detection Lidar **(CDL)
-         1.053 μm  at 5 kHz ,  48 μJ/pulse

**CMR**

**CDL**

## Example of Lidar Data

## Proteus Payload  -  In-situ Instrumentation

**Proteus Payload  -**  **In-situ Instrumentation**

** ****MET Package**
-  Buck Research CR-2 Cryogenic Hygrometer, -100oC, 20 s response
-   Near-ir laser absorption spectrometery, 1 ppmv, 50 Hz response
-  Micro Air Data Transducer (MADT)
- static pressure, differential pressure,  total air temp,
- static air Temp, dh/dt, height, true air speed, indicated air speed
** ****Best Aircraft Turbulence Probe **
** **measured wind speed and direction at 50 Hz
**Cloud, Aerosol, and Precipitation Spectrometer**
- cloud and aerosol spectrometer (CAS: 0.35 – 50 μm)
- cloud imaging probe (CIP: 25 – 1550 μm)
- liquid water content detector (LWC: 0.01 – 3 gm-3)
** ****Cloud Integrating Nephelometer **(CIN)
-  measures asymmetry parameter and extinction coefficient
** ****Video Ice Particle Sampler **(VIPS)
-  sizes between 10-200 μm
** ****Nevzorov Probe **(NEV), LWC, TWC** **
-  0.003 – 3 gm-3, sensitivity:  0.003 gm-3

**NEV**

**pitot**

**VIPS**

**CR-2**

**TAT**

**CIN**

**CAPS**

## VIPS: Measuring Crystal Shape & Size Distributions

- Size distribution generated through automatic particle recognition from NIH software

## Future Missions

**Future Missions**

**  ****Fall 04,  North Slope Alaska (NSA)**
** ****vertical structure of mixed-phase clouds**
** ****Winter 06, Tropical western Pacific (TWP)**
** ****cirrus/radiative interactions associated with monsoon convection**

**www.arm.gov**

## Have UAVs reached full potential?

- No:
**UAV cost, reliability/maintenance, availability, and airspace access need to improve**
**BUT:**
**	****UAVs offer unique capabilities for important science applications**
**	****Equipment and operational capabilities have been developed**

## Science Issues for UAVs

- What can be done if we had routine long duration UAV flights that we cannot do now?

## Aerosol/Cloud Vertical Profiles

- Representing vertical distributions of aerosols, their mixing scenarios, size distributions & single-scattering properties crucial for different regions
- Includes measurements in cloud layers!
- Observations needed in many different regions
- Different vertical profiles & meteorological forcing
- Critical for radiative and thermodynamic forcing of aerosols
- How representative are surface aerosol measurements of aerosol properties in cloud layers?

## Complete Life Cycles/Parcel Studies

- Satellites have at best hourly resolution and can’t resolve fine-scale phenomena
- Trade wind cumuli have pretty short life cycles
- Field observations don’t allow us to track complete life cycle (e.g., evolution of anvil associated with deep convection in Tropics)
- Long duration platform might allow to track Saharan dust event, or brown cloud from Asia as it transits Pacific

## Scaling Issues

- Need to go from ground-based measurements to long space/time scales of satellites
- Field experiments last only hours; satellites years long
- More routine observations in several locations would be helpful
- E.g., UAV spectral radiance measurements above ground-station would help scale between MODIS type retrievals and ground-based cloud retrievals

## Summary

- Unique set of instruments for airborne in-situ and remote sensing capabilities
- Upcoming experiments offer unique opportunity for acquiring data on cloud-radiation interactions
- Ongoing activities will attempt to further take advantage of UAV technology
- Long duration platform for tracking whole life cycle
- More routine climate tropospheric interactions not currently available

##  UW Scanning HIS:  1998-Present(HIS: High-resolution Interferometer Sounder, 1985-1998)

**	**_**Characteristics**_
**Spectral Coverage****:**  3-17 microns
**Spectral Resolution****:**    0.5 cm-1
**Resolving power:**      1000-6000
**Footprint Diam:** 1.5 km @ 15 km
**Cross-Track Scan:** Programmable
-   including uplooking zenith view

** ****Radiances for ****      Radiative Transfer**
** ****Temp & Water Vapor ****      Retrievals**
**Cloud Radiative Prop****.**
** ****Surface Emissivity & T**
** ****Trace Gas Retrievals**

_**Applications:**_

## Proteus performance characteristics

**Proteus performance characteristics**

**Altitude record (10/25/00): ****	****62,786 feet (peak)**
**	****	****	****	****61,919 feet (sustained)**
**	****	****	****	****55,786 feet (w/1000 kg payload)**
**Stall speed: ****	****	****	****65 knots**
**Top speed: ****	****	****	****250 knots/M=0.6**
**Loiter (14,000 lb takeoff wt):****	****22 hours @ 500 nmi radius****	****	****	****	****	****12 hours @ 2000 nmi****	**

## ARM-UAV/Proteus payload arrangement

- <date/time>

**ARM-UAV/Proteus payload arrangement**