Midterm

Question 1

Random error analysis equation

Answer 1

Know

Question 2

1st / 2nd order response

Answer 2

Think motion on a line vs oscillation

1st order is Mercury thermometer

2nd order is wind vane (because oscillation and damping)

Question 3

NIST

Answer 3

National Institute of Standards and Technology

Question 4

NWS

Answer 4

National Weather Service

Question 5

NOAA

Answer 5

National Oceanic and Atmospheric Administration

Question 6

BIPM

Answer 6

Bureau International des Poids et Mesures

Question 7

SI

Answer 7

Systeme International

Question 8

NEXRAD

Answer 8

Next Generation Radar

Question 9

IRT

Answer 9

Infrared Thermometer

Question 10

PRT

Answer 10

Platinum Resistance Thermometer

Question 11

RTD

Answer 11

Resistance Temperature Device

Question 12

GOES

Answer 12

Geostationary Operational Environmental Satellite

Question 13

POES

Answer 13

Polar Operational Environmental Satellite

Question 14

ARB

Answer 14

Air Resource Board (or CARB for California)

Question 15

DWR

Answer 15

Department of Water Resources

Question 16

CIMIS

Answer 16

California Irrigation Management Information System

Question 17

Basic Electricity Equations:

• resistance in series
• resistance in parallel
• voltage divider

Answer 17

in series: add resistances
in parallel: R_total = (1) / [1/R_1 + 1/R_2 + … + 1/R_n ]

loop rule

Question 18

Convert Celsius to Fahrenheit

Answer 18

T_F = (9/5)T_C + 32

Question 19

Convert miles to kilometers

Answer 19

1 mile = 1.609 km

Question 20

Convert pounds to kilograms

Answer 20

1 kg = 2.205 lbs

Question 21

Kurtosis

Answer 21

In a distribution…

low kurtosis: small “tails” = few outliers

high kurtosis: large “tails” = lots of outliers

Question 22

Skewness

Answer 22

negative skew = “skewed left” = long tail on the left

positive skew = “skewed right” = long tail on the right

Question 23

primary standards, secondary standards, tertiary…

Answer 23

primary: taken as true value
secondary: calibrated against primary
tertiary: …

Question 24

input

Answer 24

actual variable (i.e. atmospheric conditions) and standards (to calibrate instrument)

Question 25

output

Answer 25

observable variable that can be "tranduced" measured then converted to the desired quantity, (i.e. length converted to temperature)

Question 26

repeatability

Answer 26

instrument gives same value for same standards

Question 27

resolution

Answer 27

smallest detectable change in variable

Question 28

drift v. stability

Answer 28

stable: low drift from calibration over time drift: speed in which instrument slips from calibration over time

Question 29

hysteresis

Answer 29

whether previous recorded values affect future measurements (e.g. humidity sensor which retains moisture)

Question 30

linearity

Answer 30

between input and output variables: | need only to measure and calibrate at 2 values to get relationship equation

Question 31

threshold

Answer 31

e.g. wind speed propellor anemometer which wont spin (overcome static friction) until a certain threshold is met ...could also reach maximum above which propellor couldnt spin faster

Question 32

durability

Answer 32

is it operational under less than ideal conditions

Question 33

time constant

Answer 33

period in which instrument reacts to fluctuation to within 37% of new value

Question 34

NCAR

Answer 34

National enter for atmospheric research

Question 35

NPL

Answer 35

National Physics Laboratory | UK euivalent to NIST

Question 36

IRGA

Answer 36

Infrared gas analyzer

Question 37

ITS-90

Answer 37

International temperature scale 1990

Question 38

IPTS-68

Answer 38

International Practical Temperature Scale 1968

Question 39

Thermocouple principles

Answer 39

Seebeck: voltage gradient proportional to temp gradient Peltier Effect: current through dissimilar metals creates HEAT

Question 40

Thermistors

Answer 40

Semiconductors: resistance temperature devices - resistance decreases with temperature - band gap Conductors: resistance increases with temp

Question 41

Thermal radiometers

Answer 41

Radiation heats sensor: Temperature difference between (heavy) base (reference) and sensor is measured. Semiconductors: radiation in photon causes electrons to jump band gap

Question 42

Time response equation

Answer 42

(T_inf - T(t)) / (T_inf - T_initial) = exp(-t/Tau)

Question 43

Error propogation (Systematic)

Answer 43

Systematic: Total Error F (delta F) = = (partial F w.r.t. measurment 1)(error in 1) + (partial F w.r.t. measurment 2)(error in 2) +...

Question 44

Error propogation (random)

Answer 44

(Random error of F (sigma F)) = = sqrt( (partial F w.r.t. var 1 × random error in var 1 )'2 + .......)