 NCL Home > Documentation > Functions > Heat stress

# heat_swamp_cooleff

Compute the swamp cooler temperatures at 65% amd 80% efficiency. Available in version 6.4.0 and later.

## Prototype

```load "\$NCARG_ROOT/lib/ncarg/nclscripts/csm/heat_stress.ncl"  ; This library is automatically loaded
; from NCL V6.5.0 onward.
; No need for user to explicitly load.

function heat_swamp_cooleff (
t          : numeric,
twb        : numeric,
iounit  : integer,
opt        : integer
)

return_val [variable of type list containing two variables wuth the same dimensionality as t] :  float or double
```

## Arguments

t

Scalar or array containing temperature(s) [ units see iounit(0) ].

twb

Scalar or array containing wet bulb temperature [ units must match t ].

opt

Currently not used. Set to 0.

## Return value

A scalar or an array of the same size and shape as t. The output will be double if t or twb is of type double. The calculated quantity is unitless.

## Description

Given temperature and wet-bulb temperature Compute swamp cooler efficiency at 65% (poorly maintained) and 80% (well maintained)

```
REFERENCES:

Buzan, J.R. et al (2015):
Implementation and comparison of a suite of heat stress metrics
within the Community Land Model version 4.5
Geosci. Model Dev., 8, 151-170, 2015
www.geosci-model-dev.net/8/151/2015/    doi:10.5194/gmd-8-151-2015
```

## Examples

Example 1:

```   t   = 30.25      ; C
twb = 25.5       ; C
iou = (/0,0/)    ; (/C,C/)

swp8065  = heat_swamp_cooleff(t, twb, iou, 0)
swp80    = swp8065        ; extract '80%' from list variable; convenience only
swp65    = swp8065        ; extract '65%'
delete(swp8065)                  ; no longer needed

print(swp80)
print(swp65)

```
The output is
```
Variable: swp80
Type: float
Total Size: 4 bytes
1 values
Number of Dimensions: 1
Dimensions and sizes:	
Coordinates:
Number Of Attributes: 2
long_name :	Swamp Cooler: 80% Efficient
units :	degC
(0)	26.45

Variable: swp65
Type: float
Total Size: 4 bytes
1 values
Number of Dimensions: 1
Dimensions and sizes:	
Coordinates:
Number Of Attributes: 2
long_name :	Swamp Cooler: 65% Efficient
units :	degC
(0)	27.1625

```