Calculate_DO_in_ppm.ipynb

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 "cells": [
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Input variables below for calculation then run all cells"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Input salinity in PSU, temperature as deg C, oxygen as percentage sat. input pressure if sampel taken at significant depth (db)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 91,
   "metadata": {},
   "outputs": [],
   "source": [
    "MEASURED_OXYGEN_SAT = 75\n",
    "\n",
    "MEASURED_SALINITY = 35\n",
    "MEASURED_TEMPERATURE = 20\n",
    "\n",
    "MEASURED_PRESSURE = 0"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 92,
   "metadata": {},
   "outputs": [],
   "source": [
    "import seawater as sw"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### satO2 calculates the maximum solubility (saturation) of Oxygen in seawater"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### sw.satO2(s, t) where s=Salinity (psu), t=Temperature (deg C) returns O2 in ml/l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 93,
   "metadata": {},
   "outputs": [],
   "source": [
    "max_saturation = sw.satO2(MEASURED_SALINITY, MEASURED_TEMPERATURE)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 94,
   "metadata": {},
   "outputs": [],
   "source": [
    "measured_oxygen_ml = (MEASURED_OXYGEN_SAT / 100) * max_saturation"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 95,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "3.873852737352249"
      ]
     },
     "execution_count": 95,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "measured_oxygen_ml"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Measured oxygen is dissolved oxygen in ml/l units, this needs to be covnerted to mg/l"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 96,
   "metadata": {},
   "outputs": [],
   "source": [
    "measured_oxygen_mg = measured_oxygen_ml * 1.42903"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 97,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5.535851777258484"
      ]
     },
     "execution_count": 97,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "measured_oxygen_mg"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### If this isn't a particularly deep sample you can just assume that mg/l is accurate enough and use that as a rough conversion to ppm"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 98,
   "metadata": {},
   "outputs": [],
   "source": [
    "measured_oxygen_ppm = measured_oxygen_mg"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 99,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5.535851777258484"
      ]
     },
     "execution_count": 99,
     "metadata": {},
     "output_type": "execute_result"
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   ],
   "source": [
    "measured_oxygen_ppm"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### If this is a deep sample and pressure is drastically different water density will need to be taken into account"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### sw.eos80.dens(s, t, p) where s=Salinity (psu), t=Temperature (deg C), p=Pressure (db) returns sw density (kg m3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 100,
   "metadata": {},
   "outputs": [],
   "source": [
    "seawater_density = sw.eos80.dens(MEASURED_SALINITY, MEASURED_TEMPERATURE, MEASURED_PRESSURE)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 101,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1024.761739872735"
      ]
     },
     "execution_count": 101,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "seawater_density"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 102,
   "metadata": {},
   "outputs": [],
   "source": [
    "measured_oxygen_mg_per_kg = measured_oxygen_mg * (seawater_density / 1000)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 103,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5.672929098940977"
      ]
     },
     "execution_count": 103,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "measured_oxygen_mg_per_kg"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 104,
   "metadata": {},
   "outputs": [],
   "source": [
    "measured_oxygen_mgkg_ppm = measured_oxygen_mg_per_kg"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Most accurate measurement given in ppm units below"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 105,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5.672929098940977"
      ]
     },
     "execution_count": 105,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "measured_oxygen_mgkg_ppm"
   ]
  }
 ],
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