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module3/exo3/exercice_en.ipynb

@@ -7,6 +7,21 @@
     "# Subject 1: CO2 concentration in the atmosphere since 1958"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This notebook explores the long-term dataset of atmospheric CO₂ concentrations collected at the **Mauna Loa Observatory**, known as the **Keeling Curve**.\n",
+    "\n",
+    "Primary objectives:\n",
+    "\n",
+    "- Visualize the CO₂ trend and seasonal variations\n",
+    "- Separate the seasonal component\n",
+    "- Fit a linear trend model\n",
+    "- Forecast the CO₂ level up to 2025\n",
+    "- Compute yearly statistics"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -18,7 +33,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Since 1958, American scientists Charles David Keeling has performed continuous measurement of atmospheric carbon dioxide (CO2) at the Mauna Loa Observatory in Hawaii.This long-term dataset has become known as the Keeling Curve, serving as clear evidence of the ongoing increase in atmospheric CO2 concentrations, which is primarily caused by human acttivity.\n",
+    "Since 1958, American scientists Charles David Keeling has performed continuous measurement of atmospheric carbon dioxide (CO2) at the Mauna Loa Observatory in Hawaii.This long-term dataset has become known as the Keeling Curve, serving as clear evidence of the ongoing increase in atmospheric CO2 concentrations, which is primarily caused by human activity.\n",
     "\n",
     "The initial objective of the observations was to study seasonal variation in CO2, which was occured because of natural processes such as photosynthesis and respiration. Over time, however, the focuses eventually turned to understanding the long-term upward trend in the context of climat change.This was occured due to the steady year over year increase in CO2 concentrations provided measurable evidence of impact of human activities, particularly fossil fuel combustions on the global ecosystem."
    ]
@@ -36,7 +51,7 @@
     "- to create a plot showing the superposition of seasonal oscillations and a slower systematic trend.\n",
     "- to separate the seasonal component and describe it.\n",
     "- to construct a model for the long-term trend and estimates its parameters, i.e. slope and offset.\n",
-    "- to extrapolate the trend-up to the year 2025, providing a forecast for future changes in concetration of CO2 in atmosphere.\n",
+    "- to extrapolate the trend-up to the year 2025, providing a forecast for future changes in concentration of CO2 in atmosphere.\n",
     "\n",
     "The data used in this quantitative analysis is a local copy of CO2 observations from the [Scripps CO2 Program](https://scrippsco2.ucsd.edu/data/atmospheric_co2/primary_mlo_co2_record.html)."
    ]
@@ -275,7 +290,7 @@
     "Moreover, the average seasonal variation in CO2 concentration is observed accros differnt months of the year.\n",
     "Notably, CO2 levels peak in May, when plant growth has not yeat removed considerable amount of CO2 from the atmosphere.\n",
     "Conversely, the lowes concentration occur in September and October, due to enhanced photosyntetic actrivity during summer, when vegetation actively absorbs CO2.\n",
-    "After October, CO2 concentrations behin to rise again, mainly because deciduous plants shed their leaves, and photosynthesis slows down, while decomposition process continue, realising CO2 back into the atmosphere. This seasonal CO2 cycle leads to the regular annual fluctuation in its concentration."
+    "After October, CO2 concentrations begin to rise again, mainly because deciduous plants shed their leaves, and photosynthesis slows down, while decomposition process continue, realising CO2 back into the atmosphere. This seasonal CO2 cycle leads to the regular annual fluctuation in its concentration."
    ]
   },
   {
@@ -325,7 +340,7 @@
     "We construct a linear regression model to estimate the long-term trend in CO2 concentration:\n",
     "\n",
     "- the model was computed manually using the least squares method.\n",
-    "- The tren was extrapolated to predict CO2 level up to the year 2025."
+    "- The trend was extrapolated to predict CO2 level up to the year 2025."
    ]
   },
   {