Climate flow chart

Question

I am trying to draw the following "flowchart"

After some fiddling I was able to come up with the following solution

What I am struggling with mainly boils down to two things

How can I align the arrows so that they hit the boxes at straight angles? Right now I guessed, and approximated where to put them.
Is there an easy way to obtain fat arrows as displayed in the image?

Any alternative solutions to obtain the desired image are welcome as always.

Code for my attempt

\documentclass{article} 

\usepackage{xcolor}
\definecolor{UiT-main}{HTML}{003349}
\definecolor{UiT-red}{HTML}{CB333B}
\definecolor{UiT-blue}{HTML}{007396}
\definecolor{UiT-cyan}{HTML}{59BEC9}
\definecolor{UiT-orange}{HTML}{F2A900}

\usepackage{tikz}
\usetikzlibrary{shapes,arrows,calc}

% Define block styles
\tikzstyle{sun} = [circle,minimum height=0.6cm, draw, fill=UiT-orange, 
text width=4.5em, text badly centered, node distance=3cm, inner sep=0pt]
\tikzstyle{sunEmpty} = [circle,minimum height=0.6cm, 
text width=4.5em, text badly centered, node distance=3cm, inner sep=0pt]
\tikzstyle{block} = [rectangle, draw, fill=green!20, 
text width=20em, text centered, minimum height=4em]
\tikzstyle{line} = [draw, -latex']

\begin{document}

\begin{tikzpicture}[node distance = 2cm, auto]
% Place nodes
\node [sun] (Sun) {Sun};
\node [sunEmpty,right of=Sun] (SunEmpty) {};
\node [block, right of=Sun, yshift=-2cm] (greenhouse) {Greenhouse layer};
\node [block, fill=black!20, below of=greenhouse, yshift=-2cm] (surface) {surface};
% Draw edges  
\path [line] (Sun) -- node {}($(surface.north west)!0.23!(surface.north east)$);
\path [line,shorten <=0.25cm,shorten >=0.25cm] (surface) -- node {}(greenhouse);
\path [line] ($(greenhouse.north west)!0.64!(greenhouse.north east)$) -- node {}(SunEmpty.north);
\end{tikzpicture}
\end{document}

One way could be Fancy arrows with TikZ although is not ideal because you'll have to deal with nodes and not paths. — Claudio Fiandrino, Aug 06 '19 at 11:28
@ClaudioFiandrino Such arrows have been turned into a to path in this answer. — , Aug 06 '19 at 13:52
@user121799: thanks for pointing it out :) Let me also briefly say I'm sad to hear you are quitting: you did impressive contributions to the community! — Claudio Fiandrino, Aug 06 '19 at 14:45
@ClaudioFiandrino Thanks for the kind words! As I said several times, I am very grateful for your nice packages. I use thema lot (and hope you do not mind that I occasionally "hacked" them ;-). — , Aug 06 '19 at 15:23

score 4 · Accepted Answer · edited Jun 10 '20 at 12:32

How can I align the arrows so that they hit the boxes at straight angles? Right now I guessed, and approximated where to put them.

The coordinate (surface.north-|sun) will have x-coordinate value of sun and y-coordinate value of surface.north. So the path below will be hitting the box (surface) in straight angle

\path (Sun) -- (surface.north-|Sun);

Is there an easy way to obtain fat arrows as displayed in the image?

Increase line width.

Also, adjusted the outer sep of nodes so that arrows won't touch the nodes.

MWE

\documentclass[margin=3mm]{standalone} 
\usepackage{xcolor}
\usepackage{tikz}
\definecolor{UiT-main}{HTML}{003349}
\definecolor{UiT-red}{HTML}{CB333B}
\definecolor{UiT-blue}{HTML}{007396}
\definecolor{UiT-cyan}{HTML}{59BEC9}
\definecolor{UiT-orange}{HTML}{F2A900}
% Define block styles
\tikzset{sunEmpty/.style={circle,minimum height=0.6cm, 
text width=4.5em, text badly centered, node distance=3cm, inner sep=0pt, outer sep=1mm},
sun/.style={sunEmpty,draw,fill=UiT-orange},
block/.style={rectangle, draw, fill=green!20,
text width=20em, text centered, minimum height=4em, outer sep=1mm},
line/.style={-latex, line width=1.8mm, draw=blue!40}}
\begin{document}
\begin{tikzpicture}[node distance = 2cm, auto]
% Place nodes
\node [sun] (Sun) {Sun};
\node [sunEmpty,right of=Sun] (SunEmpty) {};
\node [block, right of=Sun, yshift=-2cm] (greenhouse) {Greenhouse layer};
\node [block, fill=black!20, below of=greenhouse, yshift=-2cm] (surface) {surface};
% Draw edges

\path [line,UiT-orange] (Sun) -- (surface.north-|Sun);
\path [line] (surface) -- (greenhouse);
\path [line] (greenhouse.north-|SunEmpty) -- (SunEmpty.north);
\end{tikzpicture}
\end{document}

EDIT - A better version (thanks to user121799)

\documentclass[margin=3mm,tikz]{standalone} 
\usetikzlibrary{shapes.arrows,calc,shadows.blur,positioning}
\definecolor{UiT-main}{HTML}{003349}
\definecolor{UiT-red}{HTML}{CB333B}
\definecolor{UiT-blue}{HTML}{007396}
\definecolor{UiT-cyan}{HTML}{59BEC9}
\definecolor{UiT-orange}{HTML}{F2A900}
% Define block styles
\tikzset{sun/.style={circle,minimum height=0.6cm, draw, fill=UiT-orange, 
text width=4.5em, text badly centered, node distance=3cm, inner sep=0pt, outer
sep=1mm},
sunEmpty/.style={circle,minimum height=0.6cm, 
text width=4.5em, text badly centered, node distance=3cm, inner sep=0pt, outer
sep=1mm},
block/.style={rectangle, draw, fill=green!20, 
text width=20em, text centered, minimum height=4em, outer sep=1mm},
line/.style={-latex, double arrow, line width=1.8mm, draw=blue!40}}
\begin{document}
\begin{tikzpicture}[node distance = 2cm, auto,
  fat arrow/.style={% https://tex.stackexchange.com/a/432147/121799
      to path={
        let \p1 = ($(\tikztotarget)-(\tikztostart)$),
            \n1 = {int(mod(scalar(atan2(\y1,\x1))+360, 360))}, % calculate angle in range [0,360)
            \n2 = {veclen(\x1,\y1)}
        in
        -- (\tikztotarget)
        node[inner xsep=0pt,inner ysep=5pt, % use inner ysep to set width
             minimum height=\n2-\pgflinewidth,
             single arrow,midway,sloped,anchor=center,
             #1          % arguments passed to fat arrow added here
             ] {} \tikztonodes}
  },
  fat arrow/.default=, % empty default for argument of fat arrow
  pft/.style={single arrow,draw=blue,blur
shadow,xshift=-2pt,minimum width=10mm, single arrow head extend=.2cm }
]
% Place nodes
\node [sun,blur shadow] (Sun) {Sun};
\node [sunEmpty,right=2.2cm of Sun] (SunEmpty) {};
\node [block, right of=Sun, yshift=-2cm,blur shadow,rounded corners=2pt] (greenhouse) {Greenhouse layer};
\node [block, fill=black!20, below of=greenhouse, yshift=-2cm,blur shadow,rounded corners=2pt] (surface) {surface};
% Draw edges

\path [fat arrow={pft,top color=UiT-orange!80,bottom color=UiT-orange}]
(Sun.south) to (surface.north-|Sun) ;
\path [fat arrow={pft,top color=blue!20,bottom color=blue!40}]
(surface.north) to (greenhouse.south);
\path [fat arrow={pft,top color=blue!20,bottom color=blue!40,minimum width=5mm}]
(greenhouse.north-|SunEmpty) to (SunEmpty.north);
\path [fat arrow={pft,top color=blue!20,bottom color=blue!40,minimum width=5mm}]
(greenhouse.south-|SunEmpty) to (surface.north-|SunEmpty);
\end{tikzpicture}
\end{document}

You could use this answer to make the code more elegant and easy to use. — , Aug 06 '19 at 13:30

Climate flow chart

Code for my attempt

1 Answers1

MWE

EDIT - A better version (thanks to user121799)