Global System For Monitoring Earth Radiation Balance

Llian Breen, Aaron Buys, and John Vander WeideDr. Matthew K. Heun

Calvin College, Grand Rapids, MI

Outline

The ProblemProblem ContextProposed SolutionACR TheoryACR DesignProject Objectives

Educational Context

Calvin College Senior Design Course

2004-05 Team

2003-04 Team

The Problem

Accurate measurements of Earth’s radiation Weather Models Earth Radiation Balance Is the Earth Warming?

Global Average Temperature

The Problem

Earth’s Radiation Balance

© NASA

The Problem Context

Global Radiation Balance Concept Monitor radiation directly Reduce data uncertainty Stewardship measurement?

Proposed Solution

Radiation Measurement

VS.

Satellite Scientific Balloon

ACR

Proposed Solution

Radiation Measurement

VS.

Satellite Scientific Balloon

ACR

Proposed Solution

Benefits of 35 km Radiation Measurement Increased time over target Full hemisphere data collection

ACR

Earth

Stratosphere35 km

ACR

Earth

Stratosphere35 km

ACRACRACR

Earth

Stratosphere35 km

Proposed Solution

Benefits of 35 km Radiation Measurement Reduce sources of modeling uncertainty Less modeling of vegetation and albedo

Earth

Stratosphere

35 km

Satellite800 km in orbit

Actual Measurement

Modeled Data

Estimated Vegetation Radiative Reflections

Earth

Stratosphere

35 km

Satellite800 km in orbit

Actual Measurement

Modeled Data

Actual Measurement

Modeled Data

Estimated Vegetation Radiative Reflections

Proposed Solution

Radiation Measurement Active Cavity Radiometer (ACR)

ACR Theory

Active Cavity Radiometer Active control of cavity

temperature Variation of outgoing

radiation

ACR Design

Rough Design Schematic

Design Issues Thermal

Management Cavity Geometry-

size, shape, aperture

Cavity Temperature Control

Cavity Calibration

ACR Design- Mechanical Systems

Cavity geometry designThermal Management

Cavity temperature control Cavity temperature distribution

Weather balloon interface

ACR Design- Electrical Systems

Power and heater systemFeedback system

PID – digital feedback Or PI – analog feedback

Digital conversion and storageTransmission to balloon and ground

Continuing Project

2003-04 Initial Project Development Project Proposal Demonstration ACR Prototype

2004-05 Project Continuation Finalize ACR Prototype Design Demonstration of Concept Balloon Flight

Initial Project Development

2003-04 ACR Development Thermal Model for cylindrical cavity design

Algor© Finite Element Model Numerical Model of Thermo-Electric System

Algor© Thermal Model EES© Numerical Model

220 230 240 250 260 270 280 290 3000.1

0.11

0.12

0.13

0.14

0.15

0.16

0.17

0.18

0.19

0.2

0.21

0.22

0.23

0.24

0.25

Tscene [K]

Qh

eate

r [

W]

Theoretical Calibration Curve

Initial Project Development

2003-04 ACR Development Implementation of PID temperature control Prototype ACR constructed

Cavity Aperture Cavity Side Profile

Initial Project Development

2003-04 ACR Results Prototype Calibration A/D Conversion- resolution

Active Cavity Calibration Curve

0.2

0.3

0.4

0.5

0.6

0.7

20 25 30 35 40 45 50 55

Temperature (C)

Po

wer

(W)

Active Cavity Calibration CurveExperimental Data

Project Continuation

2004-05 ACR Objectives Thermal redesign of ACR cavity Electrical controls finalization Construct prototype ACR’s Interface mech/elect with weather balloon Demonstration of Concept balloon flight

Project Objectives

2004-05 ACR Project Timeline

Prototype Modeling-

Design

End of 1st Semester

Prototype Construction-

Calibration

Interim

Fall NIAC Conference

End of 1st Semester

Balloon Flight

Jan-Feb

Data Analysis

Feb-March

Spring NIAC Conference

Mid-March

1st Semester Interim 2nd Semester

Project Objectives

2004-05 ACR Progress Obtained agreement with Global Aerospace

to use radiosonde equipment for planned prototype balloon flight in March 2005.

Questions?