# polarMotion

Calculate Earth polar motion

## Description

example

polarmotion=polarMotion(utc) calculates the movement of the rotation axis with respect to the crust of the Earth for a specific Universal Coordinated Time (UTC), specified as a modified Julian date. By default, this function uses a prepopulated list of IAU 2000A Earth orientation (IERS) data. This list contains measured and calculated (predicted) data supplied by the IERS. The IERS measures and calculates this data for a set of predetermined dates.

[polarmotion,polarmotionError]=polarMotion(utc) calculates the error for the movement of the rotation axis with respect to the crust of the Earth.

example

polarmotion=polarMotion(utc,Name,Value) calculates the movement of the rotation axis with respect to the crust of the Earth using additional options specified by one or more Name,Value pair arguments.

[polarmotion,polarmotionError]=polarMotion(utc,Name,Value) calculates the error for the movement of the rotation axis with respect to the crust of the Earth.

## Examples

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Calculate the polar motion for December 28, 2015.

mjd = mjuliandate(2015,12,28)
polarmotion = polarMotion(mjd)
mjd =
57384

polarmotion =
1.0e-05 *
0.0289    0.1233

Calculate the polar motion and polar motion error for December 28, 2015 and January 10, 2016 using the aeroiersdata.mat file. Use the mjuliandate function to calculate the date as a modified Julian date.

mjd = mjuliandate([2015 12 28;2016 1 10])
[polarmotion,polarmotionErr] = polarMotion(mjd,'Source','aeroiersdata.mat')
mjd =
57384
57397

polarmotion =
1.0e-05 *
0.0289    0.1233
0.0174    0.1304

## Input Arguments

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Array of UTC dates, specified as an M-by-1 array, represented as modified Julian dates. Use the mjuliandate function to convert the UTC date to a modified Julian date.

Data Types: double

### Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: 'Source','aeroiersdata.mat'

Custom list of Earth orientation data, specified in a MAT-file.

Out-of-range action, specified as a string.

Action to take in case of out-of-range or predicted value dates, specified as a string:

• Warning — Displays warning and indicates that the dates were out-of-range or predicted values.

• Error — Displays error and indicates that the dates were out-of-range or predicted values.

• None — Does not display warning or error.

Data Types: string

## Output Arguments

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Movement of the rotation axis with respect to the crust of the Earth, M-by-2 array, in radians.

Error for movement of the rotation axis with respect to the crust of the Earth, specified as an M-by-2 array, in radians.